Backport AVX256 load/store split patches to gcc 4.6 for performance boost on latest AMD/Intel hardware.

Richard Guenther richard.guenther@gmail.com
Tue Jun 28 09:44:00 GMT 2011


On Tue, Jun 28, 2011 at 12:33 AM, Fang, Changpeng
<Changpeng.Fang@amd.com> wrote:
> Hi,
>
> Attached are the patches we propose to backport to gcc 4.6 branch which are related to avx256 unaligned load/store splitting.
> As we mentioned before,  The combined effect of these patches are positive on both AMD and Intel CPUs on cpu2006 and
> polyhedron 2005.
>
> 0001-Split-32-byte-AVX-unaligned-load-store.patch
> Initial patch that implements unaligned load/store splitting
>
> 0001-Don-t-assert-unaligned-256bit-load-store.patch
> Remove the assert.
>
> 0001-Fix-a-typo-in-mavx256-split-unaligned-store.patch
> Fix a typo.
>
> 0002-pr49089-enable-avx256-splitting-unaligned-load-store.patch
> Disable unaligned load splitting for bdver1.
>
> All these patches are in 4.7 trunk.
>
> Bootstrap and tests are on-going in gcc 4.6 branch.
>
> Is It OK to commit to 4.6 branch as long as the tests pass?

Yes, if they have been approved and checked in for trunk.

Thanks,
Richard.

> Thanks,
>
> Changpeng
>
>
>
> ________________________________________
> From: Jagasia, Harsha
> Sent: Monday, June 20, 2011 12:03 PM
> To: 'H.J. Lu'
> Cc: 'gcc-patches@gcc.gnu.org'; 'hubicka@ucw.cz'; 'ubizjak@gmail.com'; 'hongjiu.lu@intel.com'; Fang, Changpeng
> Subject: RE: Backport AVX256 load/store split patches to gcc 4.6 for performance boost on latest AMD/Intel hardware.
>
>> On Mon, Jun 20, 2011 at 9:58 AM,  <harsha.jagasia@amd.com> wrote:
>> > Is it ok to backport patches, with Changelogs below, already in trunk
>> to gcc
>> > 4.6? These patches are for AVX-256bit load store splitting. These
>> patches
>> > make significant performance difference >=3% to several CPU2006 and
>> > Polyhedron benchmarks on latest AMD and Intel hardware. If ok, I will
>> post
>> > backported patches for commit approval.
>> >
>> > AMD plans to submit additional patches on AVX-256 load/store
>> splitting to
>> > trunk. We will send additional backport requests for those later once
>> they
>> > are accepted/comitted to trunk.
>> >
>>
>> Since we will make some changes on trunk, I would prefer to to do
>> the backport after trunk change is finished.
>
> Ok, thanks. Adding Changpeng who is working on the trunk changes.
>
> Harsha
>
>



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