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From: Thomas Koenig <tkoenig@netcologne.de>
To: Steve Kargl <sgk@troutmask.apl.washington.edu>
Cc: Richard Biener <richard.guenther@gmail.com>,
	Tobias Burnus <tobias@codesourcery.com>,
	"fortran@gcc.gnu.org" <fortran@gcc.gnu.org>
Subject: Re: MATMUL broken with frontend optimization.
Date: Fri, 19 Mar 2021 07:19:16 +0100	[thread overview]
Message-ID: <34f8dfc0-c752-c8fb-8f6b-6880b984e69c@netcologne.de> (raw)
In-Reply-To: <20210318220758.GA26001@troutmask.apl.washington.edu>


Hi Steve,

> On my old core2 cpu, a quick test with N=1000 and NxN matrix
> suggest a cross over near N=1000 for REAL(4).  This cpu doesn't
> have any AVX* instruction, so YMMV.  Program follows .sig

Looking at your data with AVX (which I think we can mostly count
on now),

- The library is always faster for matmul(vector,matrix) for any n >=100
- For matmul(matrix,vector) there is no appreciable difference

So, putting in the same inline limits for matmul(vector,matrix)
that we have for matmul(matrix,matrix), and leaving
mamul(matrix,vector) alone, seems like a reasonable thing to do.

I'll work on a patch.

Regards

	Thomas

  reply	other threads:[~2021-03-19  6:19 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-18  7:48 Steve Kargl
2021-03-18 12:35 ` Richard Biener
2021-03-18 14:48   ` Tobias Burnus
2021-03-18 15:05     ` Richard Biener
2021-03-18 16:13       ` Steve Kargl
2021-03-18 18:16         ` Thomas Koenig
2021-03-18 18:24           ` Thomas Koenig
2021-03-18 20:22             ` Steve Kargl
2021-03-18 20:55               ` Thomas Koenig
2021-03-18 22:07                 ` Steve Kargl
2021-03-19  6:19                   ` Thomas Koenig [this message]
2021-03-19  6:36                     ` Thomas Koenig
2021-03-19 19:12                       ` Steve Kargl
2021-03-19  7:03                     ` Steve Kargl

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