From: Nathan Sidwell <nathan@codesourcery.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Bernd Schmidt <bernds@codesourcery.com>,
Julian Brown <julian@codesourcery.com>,
Thomas Schwinge <thomas@codesourcery.com>,
<gcc-patches@gcc.gnu.org>
Subject: Re: [gomp4] Preserve NVPTX "reconvergence" points
Date: Mon, 22 Jun 2015 16:35:00 -0000 [thread overview]
Message-ID: <5588386A.2050902@codesourcery.com> (raw)
In-Reply-To: <20150622162039.GB10247@tucnak.redhat.com>
On 06/22/15 12:20, Jakub Jelinek wrote:
> OpenMP worksharing loop is just coordination between the threads in the
> team, which thread takes which subset of the loop's iterations, and
> optionally followed by a barrier. OpenMP simd loop is a loop that has
> certain properties guaranteed by the user and can be vectorized.
> In contrast to this, OpenACC spawns all the threads/CTAs upfront, and then
> idles on some of them until there is work for them.
correct. I expressed my question poorly. What I mean is that in openmp, a loop
that is parallelizeable (by user decree, I guess[*]), should not be transformed
such that it is not parallelizeable.
This seems to me to be a common requirement of both languages. How one gets
parallel threads of execution to the body of the loop is a different question.
nathan
[*] For ones where the compiler needs to detect parallizeablilty, it's
preferable that it doesn't do something earlier to force serializeablility.
--
Nathan Sidwell
next prev parent reply other threads:[~2015-06-22 16:31 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-28 14:20 Julian Brown
2015-05-28 14:59 ` Jakub Jelinek
2015-05-28 15:14 ` Thomas Schwinge
2015-05-28 15:28 ` Jakub Jelinek
2015-06-19 10:44 ` Bernd Schmidt
2015-06-19 12:32 ` Jakub Jelinek
2015-06-19 13:07 ` Bernd Schmidt
2015-06-19 14:10 ` Jakub Jelinek
2015-06-22 14:04 ` Bernd Schmidt
2015-06-22 14:25 ` Jakub Jelinek
2015-06-24 13:37 ` Bernd Schmidt
2015-06-24 14:08 ` Jakub Jelinek
2015-06-22 14:00 ` Julian Brown
2015-06-22 14:36 ` Jakub Jelinek
2015-06-22 15:18 ` Julian Brown
2015-06-22 15:33 ` Bernd Schmidt
2015-06-22 16:13 ` Nathan Sidwell
2015-06-22 16:27 ` Jakub Jelinek
2015-06-22 16:35 ` Nathan Sidwell [this message]
2015-06-22 17:54 ` Julian Brown
2015-06-22 18:48 ` Jakub Jelinek
2015-05-28 15:02 ` Richard Biener
2015-06-03 11:47 ` Julian Brown
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