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Groups > comp.lang.c++ > #67342
| From | scott@slp53.sl.home (Scott Lurndal) |
|---|---|
| Subject | Re: Why can't I understand what coroutines are? |
| Newsgroups | comp.lang.c++ |
| References | (4 earlier) <tZZ1F.146445$dY4.73762@fx35.iad> <1159a811-5b2d-4df6-86c3-440f2cd74eaa@googlegroups.com> <d1256257-1162-447e-b800-2d237eb168cd@googlegroups.com> <20190806221926.f30aaafc403d1bf123089913@cvine--nospam--.freeserve.co.uk> <qicue2$7gi$1@gioia.aioe.org> |
| Message-ID | <_lo2F.59970$472.24275@fx12.iad> (permalink) |
| Organization | UsenetServer - www.usenetserver.com |
| Date | 2019-08-06 23:49 +0000 |
"Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> writes: >On 8/6/2019 2:19 PM, Chris Vine wrote: >> On Tue, 6 Aug 2019 04:23:44 -0700 (PDT) >> leigh.v.johnston@googlemail.com wrote: >>> On Tuesday, August 6, 2019 at 12:13:45 PM UTC+1, leigh.v...@googlemail.com wrote: >>>> On Monday, August 5, 2019 at 6:48:18 PM UTC+1, Scott Lurndal wrote: >>>>> Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> writes: >>>>>> On 05/08/2019 02:32, Sam wrote: >>>>>>> Chris Vine writes: >>>>> >>>>>>> >>>>>>> A such, execution threads are perfect for I/O-based load. It is no wonder >>>>>>> that Linux rules the roost in TOP500 space. It's a dirty little secret >>>>>>> that all those supercomputers are just a bunch of machines with optimized >>>>>>> networking tying hundreds of thousands threads together. Yes, threads. >>>>>>> >>>>>>> Gee whiz, how can that possibly happen? >>>>>> >>>>>> epoll(...), dear. >>>>>> >>>>> >>>>> How does epoll help with high volume disk I/O? >>>> >>>> How do threads help with high volume disk I/O, dear? >>> >>> Of course by that I actually meant how does *lots* of threads help with >>> high volume disk I /O, dear? >> >> No, you have fallen victim to a classic misdirection play by Scott. The >> claim made in response to a posting of mine, originally by someone by >> the name of "Sam", was that native OS threads on linux (but not >> windows) can deal equally well with the kind of i/o things that >> coroutines are good at, and are easier to use. Both these propositions >> are in my opinion wrong, but it stands as the argument. >> >> High volume disk i/o is irrelevant to this issue, because coroutines >> aren't well suited to high volume disk i/o, nor are poll/select/epoll. >> Native threads on the other hand are reasonably well suited to this work >> load because operations on high volume disks tend to be cpu-bound and >> not i/o-bound. And apart from anything else, block devices representing >> hard disks are always signalled as ready (at any rate, they are with >> select and poll, I do not know about epoll, so poll and select are >> useless with them). >> >> The real answer to Scott is "how do coroutines help with high volume >> disk i/o"? I agree with what seems to be his suggestion - that they >> don't - so they are irrelevant to your posting about epoll. >> > >AIO should be fine, its POSIX but oh well: > >http://man7.org/linux/man-pages/man7/aio.7.html Indeed, and that's what I used in the Oracle RDMS os dependent code I wrote. (well, technically, lio_listio() because we'd submit hundreds of aiocbs with a single request - we had 128 physical disk drives on 64 SCSI controllers running Oracle Parallel Server on 64 tightly coupled P6 processors running a distributed single-system-image micro-kernel based operating system (written in C++, using cfront)). Let the OS I/O subsystem do the scheduling, don't try to do it in user mode. Note that modern network workloads that require high packet throughput generally use DPDK which provides the capability to leverage any hardware acceleration or offloading capabilities to improve I/O performance. This uses threads for parallelism. https://www.dpdk.org/ Responding to Sam's assertion regarding the TOP 500; they, for the most part, use Infiniband RDMA Verbs interface for communications between nodes, not ethernet. And it's all buried under openMP, PVM or other standard communication library APIs integrated with C and C++.
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Why can't I understand what coroutines are? Juha Nieminen <nospam@thanks.invalid> - 2019-08-04 09:37 +0000
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-04 02:58 -0700
Re: Why can't I understand what coroutines are? Sam <sam@email-scan.com> - 2019-08-04 09:18 -0400
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-04 11:15 -0700
Re: Why can't I understand what coroutines are? Louis Krupp <lkrupp@nospam.pssw.com.invalid> - 2019-08-04 04:58 -0600
Re: Why can't I understand what coroutines are? Juha Nieminen <nospam@thanks.invalid> - 2019-08-05 08:31 +0000
Re: Why can't I understand what coroutines are? Martijn van Buul <pino@dohd.org> - 2019-08-05 09:51 +0000
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-05 14:44 -0700
Re: Why can't I understand what coroutines are? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-08-04 14:08 +0100
Re: Why can't I understand what coroutines are? Sam <sam@email-scan.com> - 2019-08-04 09:23 -0400
Re: Why can't I understand what coroutines are? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-08-04 14:36 +0100
Re: Why can't I understand what coroutines are? Sam <sam@email-scan.com> - 2019-08-04 10:31 -0400
Re: Why can't I understand what coroutines are? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-08-04 16:42 +0100
Re: Why can't I understand what coroutines are? Sam <sam@email-scan.com> - 2019-08-04 16:43 -0400
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-04 13:58 -0700
Re: Why can't I understand what coroutines are? Sam <sam@email-scan.com> - 2019-08-04 17:36 -0400
Re: Why can't I understand what coroutines are? Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-08-04 22:43 +0100
Re: Why can't I understand what coroutines are? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-08-04 22:52 +0100
Re: Why can't I understand what coroutines are? Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-08-04 23:10 +0100
Re: Why can't I understand what coroutines are? Sam <sam@email-scan.com> - 2019-08-04 21:32 -0400
Re: Why can't I understand what coroutines are? Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-08-05 18:32 +0100
Re: Why can't I understand what coroutines are? scott@slp53.sl.home (Scott Lurndal) - 2019-08-05 17:48 +0000
Re: Why can't I understand what coroutines are? Sam <sam@email-scan.com> - 2019-08-05 20:14 -0400
Re: Why can't I understand what coroutines are? leigh.v.johnston@googlemail.com - 2019-08-06 04:13 -0700
Re: Why can't I understand what coroutines are? leigh.v.johnston@googlemail.com - 2019-08-06 04:23 -0700
Re: Why can't I understand what coroutines are? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-08-06 22:19 +0100
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-06 15:19 -0700
Re: Why can't I understand what coroutines are? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-08-07 00:01 +0100
Re: Why can't I understand what coroutines are? scott@slp53.sl.home (Scott Lurndal) - 2019-08-06 23:52 +0000
Re: Why can't I understand what coroutines are? Öö Tiib <ootiib@hot.ee> - 2019-08-06 16:57 -0700
Re: Why can't I understand what coroutines are? scott@slp53.sl.home (Scott Lurndal) - 2019-08-07 14:41 +0000
Re: Why can't I understand what coroutines are? Öö Tiib <ootiib@hot.ee> - 2019-08-08 07:10 -0700
Re: Why can't I understand what coroutines are? scott@slp53.sl.home (Scott Lurndal) - 2019-08-06 23:49 +0000
Re: Why can't I understand what coroutines are? Robert Wessel <robertwessel2@yahoo.com> - 2019-08-04 22:04 -0500
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-04 20:10 -0700
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-04 11:20 -0700
Re: Why can't I understand what coroutines are? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-08-04 20:30 +0100
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-04 14:03 -0700
Re: Why can't I understand what coroutines are? Paavo Helde <myfirstname@osa.pri.ee> - 2019-08-05 09:36 +0300
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-05 14:34 -0700
Re: Why can't I understand what coroutines are? scott@slp53.sl.home (Scott Lurndal) - 2019-08-04 19:46 +0000
Re: Why can't I understand what coroutines are? Juha Nieminen <nospam@thanks.invalid> - 2019-08-05 08:37 +0000
Re: Why can't I understand what coroutines are? David Brown <david.brown@hesbynett.no> - 2019-08-05 12:06 +0200
Re: Why can't I understand what coroutines are? Juha Nieminen <nospam@thanks.invalid> - 2019-08-05 12:20 +0000
Re: Why can't I understand what coroutines are? David Brown <david.brown@hesbynett.no> - 2019-08-06 15:06 +0200
Re: Why can't I understand what coroutines are? David Brown <david.brown@hesbynett.no> - 2019-08-06 15:18 +0200
Re: Why can't I understand what coroutines are? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-06 13:58 +0200
Re: Why can't I understand what coroutines are? Sam <sam@email-scan.com> - 2019-08-04 09:17 -0400
Re: Why can't I understand what coroutines are? Robert Wessel <robertwessel2@yahoo.com> - 2019-08-04 10:12 -0500
Re: Why can't I understand what coroutines are? Juha Nieminen <nospam@thanks.invalid> - 2019-08-05 08:42 +0000
Re: Why can't I understand what coroutines are? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2019-08-05 13:35 +0100
Re: Why can't I understand what coroutines are? Bart <bc@freeuk.com> - 2019-08-05 20:19 +0100
Re: Why can't I understand what coroutines are? Christian Gollwitzer <auriocus@gmx.de> - 2019-08-05 22:26 +0200
Re: Why can't I understand what coroutines are? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-08-05 23:09 +0200
Re: Why can't I understand what coroutines are? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-09 19:49 -0700
Re: Why can't I understand what coroutines are? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-08-10 05:13 +0200
Re: Why can't I understand what coroutines are? Christian Gollwitzer <auriocus@gmx.de> - 2019-08-10 08:23 +0200
Re: Why can't I understand what coroutines are? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-08-10 10:43 +0200
Re: Why can't I understand what coroutines are? Christian Gollwitzer <auriocus@gmx.de> - 2019-08-11 22:19 +0200
Re: Why can't I understand what coroutines are? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-14 08:25 -0700
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-10 00:19 -0700
Re: Why can't I understand what coroutines are? Juha Nieminen <nospam@thanks.invalid> - 2019-08-11 21:16 +0000
Re: Why can't I understand what coroutines are? "Chris M. Thomasson" <invalid_chris_thomasson_invalid@invalid.com> - 2019-08-05 23:43 -0700
Re: Why can't I understand what coroutines are? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-10 10:50 +0200
Re: Why can't I understand what coroutines are? Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk> - 2019-08-04 17:57 +0100
Re: Why can't I understand what coroutines are? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-08-05 01:11 +0200
Re: Why can't I understand what coroutines are? Juha Nieminen <nospam@thanks.invalid> - 2019-08-05 08:50 +0000
Re: Why can't I understand what coroutines are? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-08-05 16:59 +0200
Re: Why can't I understand what coroutines are? Manfred <noname@add.invalid> - 2019-08-06 16:24 +0200
Re: Why can't I understand what coroutines are? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-08-07 00:52 +0200
Re: Why can't I understand what coroutines are? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-09 18:11 -0700
Re: Why can't I understand what coroutines are? Martijn van Buul <pino@dohd.org> - 2019-08-05 07:46 +0000
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