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Groups > comp.arch > #111589 > unrolled thread
| Started by | Thomas Koenig <tkoenig@netcologne.de> |
|---|---|
| First post | 2025-05-10 11:38 +0000 |
| Last post | 2025-05-20 18:31 -0700 |
| Articles | 20 on this page of 219 — 27 participants |
Back to article view | Back to comp.arch
Is Parallel Programming Hard, And, If So, What Can You Do About It? Thomas Koenig <tkoenig@netcologne.de> - 2025-05-10 11:38 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-11 00:04 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-11 13:59 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Al Kossow <aek@bitsavers.org> - 2025-05-11 07:47 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-11 23:46 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-12 00:30 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-12 01:19 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-12 02:03 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-12 22:34 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Terje Mathisen <terje.mathisen@tmsw.no> - 2025-05-12 08:05 +0200
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-12 08:41 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-12 22:39 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-12 17:14 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-12 22:35 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-12 21:50 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-13 03:03 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-12 23:25 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-13 08:39 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? EricP <ThatWouldBeTelling@thevillage.com> - 2025-05-13 12:55 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-13 07:40 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-13 08:12 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-13 08:33 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-14 00:18 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-13 17:49 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-18 01:35 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lynn Wheeler <lynn@garlic.com> - 2025-05-18 14:10 -1000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-18 18:41 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Vir Campestris <vir.campestris@invalid.invalid> - 2025-05-19 21:46 +0100
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-19 14:58 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Vir Campestris <vir.campestris@invalid.invalid> - 2025-05-20 11:22 +0100
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lynn Wheeler <lynn@garlic.com> - 2025-05-20 16:38 -1000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-20 20:49 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-19 00:18 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-19 01:13 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-19 23:33 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-20 00:36 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-20 00:16 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-20 10:49 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-20 12:42 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-20 11:35 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-21 00:29 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-20 20:08 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-21 03:46 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-20 20:58 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? EricP <ThatWouldBeTelling@thevillage.com> - 2025-05-21 12:25 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? EricP <ThatWouldBeTelling@thevillage.com> - 2025-05-21 12:47 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-21 17:19 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? EricP <ThatWouldBeTelling@thevillage.com> - 2025-05-21 15:06 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? George Neuner <gneuner2@comcast.net> - 2025-05-21 22:19 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-22 01:51 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Torbjorn Lindgren <tl@none.invalid> - 2025-05-22 12:12 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-22 12:39 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-22 22:41 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-22 18:36 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-23 13:20 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-23 14:18 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? jseigh <jseigh_es00@xemaps.com> - 2025-05-23 12:34 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-23 11:39 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? John Levine <johnl@taugh.com> - 2025-05-23 14:21 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-23 15:17 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-23 09:57 -0700
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-23 17:43 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-23 19:26 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-24 15:25 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-24 12:32 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? John Levine <johnl@taugh.com> - 2025-05-24 20:36 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? Michael S <already5chosen@yahoo.com> - 2025-05-25 00:45 +0300
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-24 16:54 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? Terje Mathisen <terje.mathisen@tmsw.no> - 2025-05-26 22:09 +0200
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-24 21:07 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-24 17:26 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? Lars Poulsen <lars@cleo.beagle-ears.com> - 2025-05-25 20:24 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? John Levine <johnl@taugh.com> - 2025-05-25 20:47 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-25 15:51 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-25 23:23 +0000
Re: recycling "Brian G. Lucas" <bagel99@gmail.com> - 2025-05-24 17:17 -0500
Re: recycling George Neuner <gneuner2@comcast.net> - 2025-05-25 02:24 -0400
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-23 10:53 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-23 17:03 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-23 12:34 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-24 00:38 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-24 16:57 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-24 14:24 -0500
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? Thomas Koenig <tkoenig@netcologne.de> - 2025-05-30 09:20 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-24 20:38 +0000
Re: the power of junk, Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-24 16:45 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? cross@spitfire.i.gajendra.net (Dan Cross) - 2025-05-22 11:32 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-20 20:54 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-21 05:39 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-20 23:42 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-21 02:08 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-21 13:39 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-21 00:57 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-14 13:31 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? John Levine <johnl@taugh.com> - 2025-05-14 18:01 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-14 18:12 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Thomas Koenig <tkoenig@netcologne.de> - 2025-05-14 18:45 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? antispam@fricas.org (Waldek Hebisch) - 2025-05-23 00:18 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-23 05:35 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-23 01:09 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-23 12:36 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-23 11:29 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-24 03:17 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-23 08:28 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-23 17:03 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-24 09:23 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? antispam@fricas.org (Waldek Hebisch) - 2025-05-25 18:05 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-25 12:13 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-25 19:36 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-25 21:23 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? John Levine <johnl@taugh.com> - 2025-05-26 17:42 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-26 11:16 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-26 14:58 -0400
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? John Levine <johnl@taugh.com> - 2025-05-26 19:19 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-26 21:52 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-27 08:34 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-27 07:34 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-27 16:19 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-27 20:57 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-28 07:47 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-28 14:50 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-28 08:48 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-28 08:46 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-28 12:08 -0400
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-28 09:20 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-28 12:52 -0400
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-28 10:15 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-28 14:16 -0400
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-28 13:37 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-28 22:28 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-28 16:00 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-29 14:23 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-29 09:56 -0400
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? John Levine <johnl@taugh.com> - 2025-05-29 01:54 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-28 12:32 -0400
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-26 13:36 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-26 23:26 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-26 20:31 +0000
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-26 13:45 -0700
Re: fuzzy disks, Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-26 23:24 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-25 19:16 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-25 16:27 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-26 03:01 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-25 23:58 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lynn Wheeler <lynn@garlic.com> - 2025-05-26 15:36 -1000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lars Poulsen <lars@cleo.beagle-ears.com> - 2025-05-26 20:14 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-26 07:13 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-26 07:31 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? antispam@fricas.org (Waldek Hebisch) - 2025-05-26 19:20 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-26 14:12 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-30 01:42 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-29 20:25 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-30 05:53 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lynn Wheeler <lynn@garlic.com> - 2025-05-31 12:53 -1000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? John Levine <johnl@taugh.com> - 2025-06-02 18:04 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-03 07:14 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-25 15:21 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-26 06:46 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Michael S <already5chosen@yahoo.com> - 2025-05-26 16:06 +0300
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-26 16:30 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-26 13:00 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-26 13:04 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-26 14:15 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-26 15:20 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-26 15:40 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-26 16:02 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-26 16:07 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Brett <ggtgp@yahoo.com> - 2025-05-27 18:40 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-27 12:28 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-27 12:42 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Brett <ggtgp@yahoo.com> - 2025-05-29 05:10 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-29 15:31 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Brett <ggtgp@yahoo.com> - 2025-05-30 01:17 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-29 15:33 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-27 12:28 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-26 23:12 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-26 23:32 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2025-05-26 19:00 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? David Brown <david.brown@hesbynett.no> - 2025-05-27 09:43 +0200
Drive Caches (Re: Is Parallel Programming Hard, ...) Lars Poulsen <lars@cleo.beagle-ears.com> - 2025-05-25 20:55 +0000
Re: Drive Caches (Re: Is Parallel Programming Hard, ...) Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-26 00:07 -0400
Re: Drive Caches (Re: Is Parallel Programming Hard, ...) BGB <cr88192@gmail.com> - 2025-05-26 00:59 -0500
Re: Drive Caches (Re: Is Parallel Programming Hard, ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-26 07:13 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-23 22:19 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? EricP <ThatWouldBeTelling@thevillage.com> - 2025-05-23 20:51 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-17 23:57 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? quadibloc <quadibloc@gmail.com> - 2025-05-19 21:33 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-20 00:43 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-20 13:53 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? BGB <cr88192@gmail.com> - 2025-05-20 13:19 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-20 16:06 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-20 22:11 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? David Schultz <david.schultz@earthlink.net> - 2025-05-20 19:34 -0500
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-21 01:00 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-21 00:34 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? George Neuner <gneuner2@comcast.net> - 2025-05-20 21:30 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-20 18:39 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-21 03:41 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? George Neuner <gneuner2@comcast.net> - 2025-05-21 12:09 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-21 15:30 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-22 02:45 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lynn Wheeler <lynn@garlic.com> - 2025-05-21 07:06 -1000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? jseigh <jseigh_es00@xemaps.com> - 2025-05-21 17:32 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2025-05-21 07:05 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-22 02:48 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Stefan Monnier <monnier@iro.umontreal.ca> - 2025-05-21 08:23 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-21 14:08 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-22 02:49 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-22 17:34 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? scott@slp53.sl.home (Scott Lurndal) - 2025-05-22 17:42 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? mitchalsup@aol.com (MitchAlsup1) - 2025-05-23 01:54 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-22 22:42 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? George Neuner <gneuner2@comcast.net> - 2025-05-22 23:47 -0400
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-05-21 00:32 +0000
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-20 18:29 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-20 18:04 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-22 16:49 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-22 18:04 -0700
Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-05-20 18:31 -0700
Page 10 of 11 — ← Prev page 1 … 8 9 [10] 11 Next page →
| From | Stefan Monnier <monnier@iro.umontreal.ca> |
|---|---|
| Date | 2025-05-26 00:07 -0400 |
| Subject | Re: Drive Caches (Re: Is Parallel Programming Hard, ...) |
| Message-ID | <jwvldqk6n19.fsf-monnier+comp.arch@gnu.org> |
| In reply to | #111794 |
> As I see it, with variable track length geometries, the OS file
> system cannot make reasonable assumptions about track boundaries, so it
> cannot maintain track/cylinder caches, but the drive processor can.
IIUC, the 2D aspect of track/cylinder info is not sufficiently important
at that level, so the 1D approximation of it you get with current LBA
addressing gets you most of the benefit, and a small amount of buffering
(with a couple of tracks' storage) is sufficient to smooth out
the difference.
>> ...
>> but HDDs are pretty damn expensive beasts nowadays (because prices have
>> not gone down for the last 10 years or so), so I guess that makes
>> the relative cost of 512MB of DRAM "negligible"?
>
> Actually, HDDs are still on a steep downward price curve.
Downward maybe, but steep?
AFAICT, a 2½" 2TB drive still costs me about CAD$115.00 (and the largest
one I can find is only 5GB) whereas I bought one in (early) 2013 for
CAD$176.29.
Admittedly, the 2013 one was 15mm thick, but it still says something
about the price curve, I think.
Stefan
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| From | BGB <cr88192@gmail.com> |
|---|---|
| Date | 2025-05-26 00:59 -0500 |
| Subject | Re: Drive Caches (Re: Is Parallel Programming Hard, ...) |
| Message-ID | <10110br$1s39r$1@dont-email.me> |
| In reply to | #111803 |
On 5/25/2025 11:07 PM, Stefan Monnier wrote: >> As I see it, with variable track length geometries, the OS file >> system cannot make reasonable assumptions about track boundaries, so it >> cannot maintain track/cylinder caches, but the drive processor can. > > IIUC, the 2D aspect of track/cylinder info is not sufficiently important > at that level, so the 1D approximation of it you get with current LBA > addressing gets you most of the benefit, and a small amount of buffering > (with a couple of tracks' storage) is sufficient to smooth out > the difference. > >>> ... >>> but HDDs are pretty damn expensive beasts nowadays (because prices have >>> not gone down for the last 10 years or so), so I guess that makes >>> the relative cost of 512MB of DRAM "negligible"? >> >> Actually, HDDs are still on a steep downward price curve. > > Downward maybe, but steep? > > AFAICT, a 2½" 2TB drive still costs me about CAD$115.00 (and the largest > one I can find is only 5GB) whereas I bought one in (early) 2013 for > CAD$176.29. > > Admittedly, the 2013 one was 15mm thick, but it still says something > about the price curve, I think. > FWIW (for upper-end of generally available drives): When I was born, an HDD might be 20MB. When I was 10, 1GB (50X) When I was 20, 200GB (20X). When I was 30, 2TB (10X) Now: ~ 10TB (5x, *) This is quickly going into diminishing returns... *: I am aware 12TB drives exist, rounding to 10 for sake of math convenience. Extrapolating forwards, assuming the same general curve shape: 2035: 25TB 2045: 32TB 2055: 35TB 2065: 36TB 2075: Still 36TB ... There are some fudge factors, but they would more effect where it hits the plateau, rather than whether or not it will hit a plateau. Actually, directly trying to directly follow the curve shows it hitting 32GB and then drives shrinking again. I switched to a different curve that stabilizes at 36TB (but applying this curve earlier does not match the known data points). Either way, end result is similar. Granted, this is ignoring "brick of Flash modules" options, but Moore's law is also coming to an end, ... > > Stefan
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| From | anton@mips.complang.tuwien.ac.at (Anton Ertl) |
|---|---|
| Date | 2025-05-26 07:13 +0000 |
| Subject | Re: Drive Caches (Re: Is Parallel Programming Hard, ...) |
| Message-ID | <2025May26.091301@mips.complang.tuwien.ac.at> |
| In reply to | #111794 |
Lars Poulsen <lars@cleo.beagle-ears.com> writes: >Actually, HDDs are still on a steep downward price curve. The amount of >HDD space you get for USD 100 keeps going up, up, up. Actually, we have had a plateau for almost a decade where the density hardly grew: In <2018Oct19.091516@mips.complang.tuwien.ac.at> I wrote: |Robert Wessel <robertwessel2@yahoo.com> writes: [...] |>Short term variations of growth are hard deal with in any sort of |>projection, but if you look at the time between 1TB and 10TB disks, |>January 2007 through December 2015, or 106 months, you get a doubling |>once every 31.9 months (that wasn't actually the source for my 30 year |>estimate, but it happens to work out about the same way). | |Looking closer at that development, we see a growth to 3TB until |August 2010 (23.3 months per doubling), from 3TB to 4TB until |September 2011 (31.3 months per doubling), and 38.6 months per |doubling from 4TB to 10TB. | |And if we look at the development since then, we got a 14TB SMR drive |in October 2017 (45.3 months per doubling from 10TB to 14TB); this |drive is no longer being sold; all drive manufacturers now sell PMR |drives. No further growth has happened in the last year. Growth until about a year ago or so was even slower: size since 16TB 2019 18TB 2020 20TB 2021 22TB 2022 24TB 2023 26TB 2024 (Method: looking at the "gelistet seit" entries on <https://geizhals.eu/?cat=hde7s>). And consequently, the price per GB has not gone down much. E.g., looking at the cheapest 16TB drive today, it's price started with an early-adopter price of EUR 529 in 2019-07-11, went down to EUR 310 by 2021-03-07, and in the last 4 years only went down to EUR 240 (with a low point of EUR 213 last summer) <https://geizhals.eu/?phist=2068349&age=9999>. So not a particularly steep slope in the last 4 years. Supposedly the drive manufacturers have now finally managed to make HMR technology fit for the mass-market, and they promise much faster growth during the next decade; and that would consequently lead to getting a faster growth in the amount of HDD space one gets for the money. We will see if that really works out. - anton -- 'Anyone trying for "industrial quality" ISA should avoid undefined behavior.' Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-05-23 22:19 +0000 |
| Message-ID | <100qsa0$9rn7$1@dont-email.me> |
| In reply to | #111759 |
On Fri, 23 May 2025 08:28:44 -0700, Stephen Fuld wrote: > And if you are caching writes, more cache gives you more blocks to > choose from when optimizing the write back order ... Fun fact: It seems to be part of the spec that write cache reordering is disabled if the driver is using NCQ. Assuming drives pay attention to that part of the spec, of course. See the description of the “wcreorder” setting here <https://manpages.debian.org/smartctl(8)>.
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| From | EricP <ThatWouldBeTelling@thevillage.com> |
|---|---|
| Date | 2025-05-23 20:51 -0400 |
| Message-ID | <RK8YP.19901$WUcf.14574@fx01.iad> |
| In reply to | #111769 |
Lawrence D'Oliveiro wrote: > On Fri, 23 May 2025 08:28:44 -0700, Stephen Fuld wrote: > >> And if you are caching writes, more cache gives you more blocks to >> choose from when optimizing the write back order ... > > Fun fact: It seems to be part of the spec that write cache reordering is > disabled if the driver is using NCQ. > > Assuming drives pay attention to that part of the spec, of course. > > See the description of the “wcreorder” setting here > <https://manpages.debian.org/smartctl(8)>. Referring to the wcreorder flag, it doesn't say it disables reordering. It says "The state of Write Cache Reordering has no effect on either NCQ or LCQ queued commands.". SATA has separate commands for queued reads and writes and non-queued. It sounds like that flag controls whether non-queued commands are also reordered or not. By using a queue command you are giving permission to reorder that command. Note that most HDD drivers also do reordering (elevator algorithm). I don't know if they disable it for SATA drives with NCQ but I see no reason to as NCQ only handles up to 32 commands whereas driver reorder optimization applies to the whole disk queue.
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-05-17 23:57 +0000 |
| Message-ID | <100b7pu$kn2g$2@dont-email.me> |
| In reply to | #111600 |
On Mon, 12 May 2025 22:35:57 -0000 (UTC), I wrote: > In other words, telling lies to the OS that the write has completed > when it hasn’t. This kind of thing can really stuff up filesystem > integrity guarantees. What do you know, it turns out there is this feature, originally from SCSI and part of NCQ, called “Force Unit Access” (FUA) <https://en.wikipedia.org/wiki/Disk_buffer#FUA>. But do we really know that the drive vendors will honour this command ... ?
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| From | quadibloc <quadibloc@gmail.com> |
|---|---|
| Date | 2025-05-19 21:33 +0000 |
| Message-ID | <27492f8028a0d40eff5071e85214fc36@www.novabbs.com> |
| In reply to | #111589 |
I think that the _title_ of the book reveals a fatal misconception about the problem with parallel programming. Parallel programming isn't "hard" or "easy". It depends on the problem you're trying to solve. For some problems, parallel programming is trivial; for some, it is possible, but is wasteful of resources - so it's only applicable if there's a genuine benefit to reducing wall-clock time, and you're not using a shared computer; and for others it isn't possible. What can be done to improve the situation is to develop *new algorithms*, and that is much more difficult than simply becoming a more disciplined programmer, which is what is usually touted as the solution. John Savard
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-05-20 00:43 +0000 |
| Message-ID | <100gj7t$1sbnn$11@dont-email.me> |
| In reply to | #111657 |
On Mon, 19 May 2025 21:33:11 +0000, quadibloc wrote: > Parallel programming isn't "hard" or "easy". Concurrent processes/threads, running either fully concurrently on separate processors, or with asynchronous preemption on shared processors, are hard to program. That’s where the term “heisenbug” came from, where you had subtle, intermittent, timing-related misbehaviour that, for example, tended to go away when you changed the code to try to narrow the problem down. In the 1990s, multithreading became popular, and people wanted to use it for everything -- even GUIs. That turned out to be a bad idea. So nowadays we recognize that threads are mainly useful to increase performance for CPU-bound code, and not much else. We also now have the async/await paradigm, also known as “stackless coroutines”. Like threads, this lets us manage multiple concurrent activities at once. Unlike threads, preemption is always explicit, which gets rid of most possibilities for race conditions. This technique is very useful where the performance bottleneck lies elsewhere than the CPU: i.e. the filesystem, network, or just waiting for the user to click the mouse or press the next key.
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| From | scott@slp53.sl.home (Scott Lurndal) |
|---|---|
| Date | 2025-05-20 13:53 +0000 |
| Message-ID | <QP%WP.57065$RXsc.38723@fx36.iad> |
| In reply to | #111665 |
Lawrence D'Oliveiro <ldo@nz.invalid> writes: >On Mon, 19 May 2025 21:33:11 +0000, quadibloc wrote: > >> Parallel programming isn't "hard" or "easy". > >Concurrent processes/threads, running either fully concurrently on >separate processors, or with asynchronous preemption on shared processors, >are hard to program. Clearly you are someone who has never done it.
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| From | BGB <cr88192@gmail.com> |
|---|---|
| Date | 2025-05-20 13:19 -0500 |
| Message-ID | <100iher$2b7vi$2@dont-email.me> |
| In reply to | #111672 |
On 5/20/2025 8:53 AM, Scott Lurndal wrote: > Lawrence D'Oliveiro <ldo@nz.invalid> writes: >> On Mon, 19 May 2025 21:33:11 +0000, quadibloc wrote: >> >>> Parallel programming isn't "hard" or "easy". >> >> Concurrent processes/threads, running either fully concurrently on >> separate processors, or with asynchronous preemption on shared processors, >> are hard to program. > > Clearly you are someone who has never done it. In my case... Personally, I rarely use multi-threading, and when I do, it is usually in the form of using mutex locks over shared buffers. You lock the mutex if needed to copy data from one thread to another; or when doing a task that depends on the data being consistent. Ironically, this is something that fairly easily maps onto a weak memory model. And is easily adapted to networked shared memory approaches as well; except that a shared-memory-system mutex is almost impractically expensive, and it may make sense to have multiple types of mutex in this case with more limited scope, say, to avoid needing to forcibly synchronize "everything". And, it almost seems like the solution to a lot of these "problems" would be more "have everyone assume that weak consistency as the default" rather than "make every CPU and every piece of hardware obey cache coherence". Or, IOW, Unless you lock the mutex, you have no idea whether the shared writable data is up-to-date. Only shared read-only data is "safe" to be accessed freely, after any initial synchronization is done. ...
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| From | Stefan Monnier <monnier@iro.umontreal.ca> |
|---|---|
| Date | 2025-05-20 16:06 -0400 |
| Message-ID | <jwvcyc3xd2v.fsf-monnier+comp.arch@gnu.org> |
| In reply to | #111677 |
> Personally, I rarely use multi-threading, and when I do, it is usually in
> the form of using mutex locks over shared buffers.
> You lock the mutex if needed to copy data from one thread to another; or
> when doing a task that depends on the data being consistent.
FWIW, I think these kinds of things usually fall in the scope of
concurrency rather than parallelism.
Stefan
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| From | mitchalsup@aol.com (MitchAlsup1) |
|---|---|
| Date | 2025-05-20 22:11 +0000 |
| Message-ID | <fcb1f88f53b1a99fae7dc50eaba94f54@www.novabbs.org> |
| In reply to | #111680 |
On Tue, 20 May 2025 20:06:13 +0000, Stefan Monnier wrote: >> Personally, I rarely use multi-threading, and when I do, it is usually >> in >> the form of using mutex locks over shared buffers. >> You lock the mutex if needed to copy data from one thread to another; or >> when doing a task that depends on the data being consistent. > > FWIW, I think these kinds of things usually fall in the scope of > concurrency rather than parallelism. When I run 20-copies of a FEM CFD application, each uni-process:: am I running concurrently ?? or in parallel ?? or both ?? Also note: I need to use the "affinity" service under taskMangler so that only 4 processes share a core, performance goes up by roughly 20%. The CFD simulations typically run for 10 hours (each, wall clock time), and every second; dump out a dozen KB of compressed data (each). The disk load is low enough I can do other "stuff" on the computer as long as I affinitize the heavy loads to 5 of the 6 cores. > > > Stefan
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| From | David Schultz <david.schultz@earthlink.net> |
|---|---|
| Date | 2025-05-20 19:34 -0500 |
| Message-ID | <hc9XP.269181$R505.210341@fx10.iad> |
| In reply to | #111682 |
On 5/20/25 5:11 PM, MitchAlsup1 wrote: > When I run 20-copies of a FEM CFD application, each uni-process:: > am I running concurrently ?? or in parallel ?? or both ?? > Reminds me of something from the 90's. The computer science department had a UNIX machine built around many 80386 CPUs. I was taking a course on Internet programming and the best editor available was vi. Ugh. So I downloaded the sources for emacs. Giving make the option to run multiple processes improved the build speed a lot. -- http://davesrocketworks.com David Schultz "The cheaper the crook, the gaudier the patter." - Sam Spade
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-05-21 01:00 +0000 |
| Message-ID | <100j8j8$2g75r$2@dont-email.me> |
| In reply to | #111687 |
On Tue, 20 May 2025 19:34:20 -0500, David Schultz wrote: > Giving make the option to run multiple processes improved the build > speed a lot. The fun thing about “make -j«nrprocesses»” is you can omit the «nrprocesses» and it will create as many processes as it can find an excuse for. Try this with something decently-sized, like an FFmpeg build, and watch your system come to its knees. ;)
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-05-21 00:34 +0000 |
| Message-ID | <100j72g$2fqhj$11@dont-email.me> |
| In reply to | #111682 |
On Tue, 20 May 2025 22:11:41 +0000, MitchAlsup1 wrote: > When I run 20-copies of a FEM CFD application, each uni-process:: > am I running concurrently ?? or in parallel ?? or both ?? I guess that depends on what your licence server says. ;) (Unless it’s open-source software, of course ...)
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| From | George Neuner <gneuner2@comcast.net> |
|---|---|
| Date | 2025-05-20 21:30 -0400 |
| Message-ID | <i3bq2klvtcl1d47i6hp9bbbi2lud240l6e@4ax.com> |
| In reply to | #111682 |
On Tue, 20 May 2025 22:11:41 +0000, mitchalsup@aol.com (MitchAlsup1) wrote: >On Tue, 20 May 2025 20:06:13 +0000, Stefan Monnier wrote: > >>> Personally, I rarely use multi-threading, and when I do, it is usually >>> in >>> the form of using mutex locks over shared buffers. >>> You lock the mutex if needed to copy data from one thread to another; or >>> when doing a task that depends on the data being consistent. >> >> FWIW, I think these kinds of things usually fall in the scope of >> concurrency rather than parallelism. > >When I run 20-copies of a FEM CFD application, each uni-process:: >am I running concurrently ?? or in parallel ?? or both ?? Processes on the same core are concurrent - processes on different cores are parallel. >Also note: I need to use the "affinity" service under taskMangler >so that only 4 processes share a core, performance goes up by roughly >20%. > >The CFD simulations typically run for 10 hours (each, wall clock time), >and every second; dump out a dozen KB of compressed data (each). The >disk load is low enough I can do other "stuff" on the computer as >long as I affinitize the heavy loads to 5 of the 6 cores. > >> >> >> Stefan
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| From | "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> |
|---|---|
| Date | 2025-05-20 18:39 -0700 |
| Message-ID | <100jata$2g8o9$3@dont-email.me> |
| In reply to | #111694 |
On 5/20/2025 6:30 PM, George Neuner wrote: > On Tue, 20 May 2025 22:11:41 +0000, mitchalsup@aol.com (MitchAlsup1) > wrote: > >> On Tue, 20 May 2025 20:06:13 +0000, Stefan Monnier wrote: >> >>>> Personally, I rarely use multi-threading, and when I do, it is usually >>>> in >>>> the form of using mutex locks over shared buffers. >>>> You lock the mutex if needed to copy data from one thread to another; or >>>> when doing a task that depends on the data being consistent. >>> >>> FWIW, I think these kinds of things usually fall in the scope of >>> concurrency rather than parallelism. >> >> When I run 20-copies of a FEM CFD application, each uni-process:: >> am I running concurrently ?? or in parallel ?? or both ?? > > Processes on the same core are concurrent - processes on different > cores are parallel. Only if the cores and/or "hardware threads" do not interfere with one another? Fwiw, an example of an embarrassingly parallel algorithm is computing the Mandelbrot set. Actually, this reminds me of the "alias" problem with Intel hyper threading in the past. > > >> Also note: I need to use the "affinity" service under taskMangler >> so that only 4 processes share a core, performance goes up by roughly >> 20%. >> >> The CFD simulations typically run for 10 hours (each, wall clock time), >> and every second; dump out a dozen KB of compressed data (each). The >> disk load is low enough I can do other "stuff" on the computer as >> long as I affinitize the heavy loads to 5 of the 6 cores. >> >>> >>> >>> Stefan
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-05-21 03:41 +0000 |
| Message-ID | <100ji1o$2lgt3$5@dont-email.me> |
| In reply to | #111696 |
On Tue, 20 May 2025 18:39:54 -0700, Chris M. Thomasson wrote: >> Processes on the same core are concurrent - processes on different >> cores are parallel. > > Only if the cores and/or "hardware threads" do not interfere with one > another? That’s why I think the distinction is meaningless. Yes, there is a valid distinction to be made between truly concurrent/ parallel processes/threads, and ones which are made to appear so by preemptive scheduling on shared hardware. Not sure if there is a good term for the latter: “timesliced”? “timeshared”? “pseudoconcurrent”? “pseudoparallel”?
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| From | George Neuner <gneuner2@comcast.net> |
|---|---|
| Date | 2025-05-21 12:09 -0400 |
| Message-ID | <1tsr2kpgl9seqn2pqgc92bo7dam355smlh@4ax.com> |
| In reply to | #111698 |
On Wed, 21 May 2025 03:41:45 -0000 (UTC), Lawrence D'Oliveiro <ldo@nz.invalid> wrote: >On Tue, 20 May 2025 18:39:54 -0700, Chris M. Thomasson wrote: > >>> Processes on the same core are concurrent - processes on different >>> cores are parallel. >> >> Only if the cores and/or "hardware threads" do not interfere with one >> another? > >That’s why I think the distinction is meaningless. > >Yes, there is a valid distinction to be made between truly concurrent/ >parallel processes/threads, and ones which are made to appear so by >preemptive scheduling on shared hardware. > >Not sure if there is a good term for the latter: “timesliced”? >“timeshared”? “pseudoconcurrent”? “pseudoparallel”? Yeah ... but recall that the terminology is passed down from the days of single core, single thread CPUs. The meanings have been bent, spindled, and mutilated by time, and conflated in general awareness. Multi-programming meant running multiple programs on a single CPU. [i.e. "concurrent" programming] Preemptive timeslicing generally was implied, but the term itself did not distinguish how programs were separated: e.g., programmatically (purely by software), segmented by partition, interleaved (with or without VMM protection), etc. Multi-processing [from multi-processor] meant running multiple processes in parallel on separate CPUs (remember, single core, single thread). Multi-threading meant being able to (pseudo)simultaneously execute along multiple "paths" within a /single/ process. The term itself did not distinguish whether this was done concurrently (single CPU) or in parallel, and also did not distinguish whether scheduling was preemtive or cooperative. Multi-tasking was a catch-all term that could mean any combination of the others. Nobody cares anymore.
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| From | Stefan Monnier <monnier@iro.umontreal.ca> |
|---|---|
| Date | 2025-05-21 15:30 -0400 |
| Message-ID | <jwvecwhixg6.fsf-monnier+comp.arch@gnu.org> |
| In reply to | #111698 |
>>> Processes on the same core are concurrent - processes on different
>>> cores are parallel.
>> Only if the cores and/or "hardware threads" do not interfere with one
>> another?
> That’s why I think the distinction is meaningless.
If you're talking about a set of processes running concurrently or in
parallel, then indeed the two terms are interchangeable, AFAIK.
If you're talking about research areas, parallelism and concurrency are
different.
In the case of concurrency the core question is: Given a set of somewhat
independent tasks working on some chunks of data, make sure the computed
result is correct, e.g. design tools like mutexes, memory barriers,
transactional memory, static analysis, reasoning principles, etc...
whose core focus is on making sure there's no race conditions, dead
locks, ...
In the case of parallelism, the core question instead is: given
a program/algorithm, restructure (or even completely replace) it so as
to divide it into somewhat independent tasks that can take advantage of
multiple CPUs to finish the work faster.
Clearly, the two overlap, but they are nevertheless fairly different.
Stefan
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