Groups > comp.arch > #2066

Re: alignment, was History of byte addressing

From	Anne & Lynn Wheeler <lynn@garlic.com>
Newsgroups	comp.arch
Subject	Re: alignment, was History of byte addressing
Date	2011-06-06 15:32 -0400
Organization	Wheeler&Wheeler
Message-ID	<m3y61en4ca.fsf@garlic.com> (permalink)
References	<is8ons$jiv$1@gal.iecc.com> <93eabd84-42a3-4f74-a96c-cc28e4dce421@v10g2000yqn.googlegroups.com> <ishvmh$tah$1@gosset.csi.cam.ac.uk> <isj6h6$6se$1@gal.iecc.com> <isj6c5$a44$1@gosset.csi.cam.ac.uk>

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nmm1@cam.ac.uk writes:
> If you want real fun, there are some shared memory codes where
> unaligned accesses can double the number of lines that are on
> the wrong core when they are needed!
>
> And, while their architecture is unusual, it isn't exempt from
> inefficiencies due to such conflicts!

aka early 80s, at least MVS & VM370 operating systems had major work
item to make internal kernel storage cache-line sensitive (i.e. started
on cache line and ended on cache-line). claim was that it got 5-6%
system thruput improvement in 4-way configuration (eliminating
cache-line thrashing where different storage areas ... in use by
different processors, shared cache line).

another way of looking at some of the current stuff ... is that relative
latencies for fetches have increased so ... there is lots of time to
overlap/mask all sorts of stuff (as well as lots of extra circuits to
perform the additional operations). for instance ... current generation
is quoted as having 50% higher thruput than previous generation ... some
comes from faster machine cycle ... but also 20% comes from the (new)
introduction of out-of-order exectuion. all those spare circuits also
help account for big expansion in instruction set ... compared to KISS
from 360 days.

one example (early instruction KISS) associated with was the
introduction of compare-and-swap.  Charlie invented compare-and-swap
(CAS are charlie's initials) when he was doing work on multiprocessor
fine-grain locking in cp67 (360/67 had test&set).  Initial attempt to
get compare-and-swap into 370 were rejected with reference to the POK
favorite-son operating system believing that (360) test-and-set was more
than adequate for multiprocessor implementations. The 370 architecture
people said that in order to get compare-and-swap included in 370
architecture some non-multiprocessor uses would have to be created. Thus
was born the multiprogramming (aka multi-threaded) application uses
(like large DBMS operations) ... being able to do various kinds of
atomic storage updates (w/o requiring kernel lock/serialization).

misc. past posts mentioning compare&swap and/or multiprocessor
http://www.garlic.com/~lynn/subtopic.html#smp

-- 
virtualization experience starting Jan1968, online at home since Mar1970

Thread

History of byte addressing John Levine <johnl@iecc.com> - 2011-06-02 19:36 +0000
  Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-02 20:38 +0100
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-03 08:05 -0700
  Re: History of byte addressing Alex McDonald <blog@rivadpm.com> - 2011-06-03 05:26 -0700
    Re: History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-03 09:48 -0400
  Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-03 07:49 -0700
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-03 10:56 -0700
  Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-04 10:59 -0700
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-04 15:01 -0700
      Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-04 22:53 +0100
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 10:40 -0700
    Re: History of byte addressing John Levine <johnl@iecc.com> - 2011-06-05 06:10 +0000
      Re: History of byte addressing Robert Myers <rbmyersusa@gmail.com> - 2011-06-05 10:00 -0700
        Re: History of byte addressing Robert Myers <rbmyersusa@gmail.com> - 2011-06-05 10:04 -0700
          Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 10:36 -0700
            Re: History of byte addressing "Paul A. Clayton" <paaronclayton@gmail.com> - 2011-06-05 11:00 -0700
              Re: History of byte addressing Morten Reistad <first@last.name> - 2011-06-05 21:42 +0200
                Re: History of byte addressing anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-06-06 17:03 +0000
                Re: History of byte addressing Andrew Reilly <areilly---@bigpond.net.au> - 2011-06-06 23:55 +0000
                Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:26 -0700
                Re: History of byte addressing Andrew Reilly <areilly---@bigpond.net.au> - 2011-06-07 05:08 +0000
                Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-07 03:26 -0700
                Re: History of byte addressing Roberto Waltman <usenet@rwaltman.com> - 2011-07-05 20:00 -0400
                Re: History of byte addressing jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-06 00:15 +0000
              Re: History of byte addressing George Neuner <gneuner2@comcast.net> - 2011-06-05 16:18 -0400
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 22:10 -0700
              Re: History of byte addressing torbenm@diku.dk (Torben Ægidius Mogensen) - 2011-06-07 10:50 +0200
                Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:02 +0200
              Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 15:51 +0200
            Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-05 13:43 -0600
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 22:12 -0700
                Re: History of byte addressing EricP <ThatWouldBeTelling@thevillage.com> - 2011-06-06 02:04 -0400
                Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-05 23:49 -0700
                Re: History of byte addressing EricP <ThatWouldBeTelling@thevillage.com> - 2011-06-06 13:34 -0400
                Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-06 10:49 -0700
                Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-06 22:42 -0700
                Re: History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-07 07:37 -0400
                Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-07 08:22 -0700
                Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-11 09:56 -0700
                Re: History of byte addressing EricP <ThatWouldBeTelling@thevillage.com> - 2011-06-11 14:59 -0400
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-11 18:52 -0600
                Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-12 12:40 -0700
                Re: History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-11 15:05 -0400
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-06 13:10 -0600
                Re: History of byte addressing George Neuner <gneuner2@comcast.net> - 2011-06-06 16:41 -0400
                Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:13 -0700
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-06 23:50 -0600
                Re: History of byte addressing Jim Haynes <jhaynes@alumni.uark.edu> - 2011-06-07 10:01 -0500
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-07 13:09 -0600
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-07 14:03 -0600
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-06 05:16 -0600
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 10:44 -0700
        Re: History of byte addressing John Levine <johnl@iecc.com> - 2011-06-06 05:00 +0000
          Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 22:11 -0700
            Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-06 08:00 +0100
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:16 -0700
            Re: History of byte addressing Michael S <already5chosen@yahoo.com> - 2011-06-06 01:01 -0700
              Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-06 08:30 +0100
                Re: History of byte addressing Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-06-06 10:34 +0200
                Re: History of byte addressing Michael S <already5chosen@yahoo.com> - 2011-06-06 03:29 -0700
                Re: History of byte addressing Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-06-06 15:21 +0200
                Re: History of byte addressing Michael S <already5chosen@yahoo.com> - 2011-06-06 03:23 -0700
                Re: History of byte addressing MitchAlsup <MitchAlsup@aol.com> - 2011-06-07 08:01 -0700
                Re: alignment, was History of byte addressing John Levine <johnl@iecc.com> - 2011-06-06 18:33 +0000
                Re: alignment, was History of byte addressing nmm1@cam.ac.uk - 2011-06-06 19:30 +0100
                Re: alignment, was History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-06 15:32 -0400
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:11 -0700
          Re: History of byte addressing Robert Myers <rbmyersusa@gmail.com> - 2011-06-06 06:48 -0700
            Re: History of byte addressing jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-03 16:13 +0000
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-03 09:10 -0700
  Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:23 +0200
    Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-07 08:26 -0700
  Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:25 +0200
    Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:45 +0200
      Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:48 +0200
      Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:59 +0200
        Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 17:05 +0200
  Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-18 15:43 -0700
  Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 03:14 -0700
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 03:40 -0700
      Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 04:28 -0700
        Re: History of byte addressing nmm1@cam.ac.uk - 2011-07-04 13:38 +0100
          Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 06:47 -0700
            Re: History of byte addressing nmm1@cam.ac.uk - 2011-07-04 14:16 +0100
        Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-04 15:53 +0100
      Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-04 15:36 +0100
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 07:50 -0700
          Re: History of byte addressing John Levine <johnl@iecc.com> - 2011-07-04 19:46 +0000
            Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 15:29 -0700
              Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-05 00:02 +0100
      Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-04 15:47 +0100
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 07:54 -0700

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