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From: Wilco Dijkstra via Libc-alpha <libc-alpha@sourceware.org>
To: "naohirot@fujitsu.com" <naohirot@fujitsu.com>,
	Noah Goldstein <goldstein.w.n@gmail.com>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH v2 2/5] benchtests: Add memset zero fill benchtest
Date: Tue, 27 Jul 2021 17:26:46 +0000	[thread overview]
Message-ID: <VE1PR08MB559949740A4249736EB6335883E99@VE1PR08MB5599.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <TYAPR01MB60257528E0236C643B1C533ADFE99@TYAPR01MB6025.jpnprd01.prod.outlook.com>

Hi Naohiro,

> There may be miscomminuation.
> The * 16 is already in the outer loop (1).

The outer loop is in test_main, and it determines 'n' in do_one_test:

  for (i = ...)
    {
      do_test (&json_ctx, 0, c, i);
    }

> Let me copy the code from the mail [1] I put in the previouse mail [2].

The key issue is that this loop:

      for (j = 0; j < 16; j++)
        CALL (impl, s + n * j, c2, n);

is equivalent to:

CALL (impl, s, c2, n * 16);

The loop we really want is something like bench-memset-large:

  CALL (impl, s, c, n);
  TIMING_NOW (start);
  for (i = 0; i < iters; ++i)
    {
      CALL (impl, s, c, n);
    }
  TIMING_NOW (stop);

This repeats CALL on data of size 'n' after an initial warmup of the caches.

> It doesn't matter what kind of memset is called, but matters the
> function name in the code so that we can understand it is not mesured.

Then using the standard name 'memset' would be best.

>> What I mean is something trivial like: CALL (impl, s, memset_array[i & 15], n);
>> This way you can test any kind of pattern (like all zero, all one, and combinations
>> with varying number of zero->non-zero and non-zero->zero transitions).
>
> I understood, thanks.
> Why don't we separate it to another patch if it is really matter?

I don't think it matters, however I thought that is what your loops try to
measure? If not, then why not use the loop from bench-memset-large?

> From AArch64 point of view, the purpose of this bench is to measure
> "DC ZVA" performance. So non-zero value can be any value except zero.
> Do we have any specific reason to vary the non-zero value?

Well if that is the goal then bench-memset-large can measure zero performance
with minor changes. If you don't need to do anything completely different then
the existing code is good enough.

Cheers,
Wilco

  reply	other threads:[~2021-07-27 17:27 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-13  8:22 [PATCH] benchtests: Add memset zero fill benchmark tests Naohiro Tamura via Libc-alpha
2021-07-13 13:50 ` Lucas A. M. Magalhaes via Libc-alpha
2021-07-20  6:31 ` [PATCH v2 0/5] " Naohiro Tamura via Libc-alpha
2021-08-05  7:47   ` [PATCH v3 0/5] benchtests: Add memset zero fill benchmark test Naohiro Tamura via Libc-alpha
2021-08-05  7:49     ` [PATCH v3 1/5] benchtests: Enable scripts/plot_strings.py to read stdin Naohiro Tamura via Libc-alpha
2021-08-05  7:56       ` Siddhesh Poyarekar
2021-09-08  1:46         ` naohirot--- via Libc-alpha
2021-09-08 12:56           ` Siddhesh Poyarekar
2021-09-09  0:22             ` naohirot--- via Libc-alpha
2021-09-13  3:45               ` Siddhesh Poyarekar
2021-08-05  7:50     ` [PATCH v3 2/5] benchtests: Add memset zero fill benchtest Naohiro Tamura via Libc-alpha
2021-09-08  2:03       ` naohirot--- via Libc-alpha
2021-09-10 20:40       ` Lucas A. M. Magalhaes via Libc-alpha
2021-09-13  0:53         ` naohirot--- via Libc-alpha
2021-09-13 14:05           ` Lucas A. M. Magalhaes via Libc-alpha
2021-09-14  0:38             ` [PATCH v4] " Naohiro Tamura via Libc-alpha
2021-09-14  0:44             ` [PATCH v3 2/5] " naohirot--- via Libc-alpha
2021-09-14 14:02               ` Wilco Dijkstra via Libc-alpha
2021-09-15  8:24                 ` naohirot--- via Libc-alpha
2021-09-21  1:27                   ` naohirot--- via Libc-alpha
2021-09-21 11:09                     ` Wilco Dijkstra via Libc-alpha
2021-09-22  1:05                       ` [PATCH v5] " Naohiro Tamura via Libc-alpha
2023-02-09 17:23                         ` Carlos O'Donell via Libc-alpha
2023-02-10  1:26                           ` Siddhesh Poyarekar via Libc-alpha
2021-09-22  1:07                       ` [PATCH v3 2/5] " naohirot--- via Libc-alpha
2021-09-28  1:40                         ` naohirot--- via Libc-alpha
2021-09-30  0:55                           ` Tamura, Naohiro/田村 直� via Libc-alpha
2021-10-18 12:57                           ` Lucas A. M. Magalhaes via Libc-alpha
2021-10-20 13:44                             ` Wilco Dijkstra via Libc-alpha
2021-10-20 15:35                               ` Lucas A. M. Magalhaes via Libc-alpha
2021-10-20 17:47                                 ` Wilco Dijkstra via Libc-alpha
2021-10-22 13:08                                   ` Lucas A. M. Magalhaes via Libc-alpha
2021-08-05  7:51     ` [PATCH v3 3/5] benchtests: Remove redundant assert.h Naohiro Tamura via Libc-alpha
2021-09-08  1:59       ` naohirot--- via Libc-alpha
2021-09-13  3:36       ` Siddhesh Poyarekar
2021-08-05  7:51     ` [PATCH v3 4/5] benchtests: Fix validate_benchout.py exceptions Naohiro Tamura via Libc-alpha
2021-09-08  1:55       ` naohirot--- via Libc-alpha
2021-09-13  3:42       ` Siddhesh Poyarekar
2021-09-13  3:50         ` Siddhesh Poyarekar
2021-09-13 13:44           ` [PATCH v4] " Naohiro Tamura via Libc-alpha
2021-09-15  3:23             ` Siddhesh Poyarekar
2021-09-16  1:12               ` naohirot--- via Libc-alpha
2021-09-16  1:41                 ` Siddhesh Poyarekar
2021-09-16  2:23                   ` [PATCH v5] " Naohiro Tamura via Libc-alpha
2021-09-16  3:48                     ` Siddhesh Poyarekar
2021-09-16  5:23                       ` naohirot--- via Libc-alpha
2021-09-16  2:26                   ` [PATCH v4] " naohirot--- via Libc-alpha
2021-09-13 13:46           ` [PATCH v3 4/5] " naohirot--- via Libc-alpha
2021-08-05  7:52     ` [PATCH v3 5/5] config: Rename HAVE_BUILTIN_MEMSET macro Naohiro Tamura via Libc-alpha
2021-08-11 20:34       ` Adhemerval Zanella via Libc-alpha
2021-07-20  6:34 ` [PATCH v2 1/5] benchtests: Enable scripts/plot_strings.py to read stdin Naohiro Tamura via Libc-alpha
2021-07-20  6:35 ` [PATCH v2 2/5] benchtests: Add memset zero fill benchtest Naohiro Tamura via Libc-alpha
2021-07-20 16:48   ` Noah Goldstein via Libc-alpha
2021-07-21 12:56     ` naohirot--- via Libc-alpha
2021-07-21 13:07       ` naohirot--- via Libc-alpha
2021-07-21 18:14         ` Noah Goldstein via Libc-alpha
2021-07-21 19:17           ` Wilco Dijkstra via Libc-alpha
2021-07-26  8:42             ` naohirot--- via Libc-alpha
2021-07-26 11:15               ` Wilco Dijkstra via Libc-alpha
2021-07-27  2:24                 ` naohirot--- via Libc-alpha
2021-07-27 17:26                   ` Wilco Dijkstra via Libc-alpha [this message]
2021-07-28  7:27                     ` naohirot--- via Libc-alpha
2021-08-04  9:11                       ` naohirot--- via Libc-alpha
2021-07-26  8:39     ` naohirot--- via Libc-alpha
2021-07-26 17:22       ` Noah Goldstein via Libc-alpha
2021-07-20  6:35 ` [PATCH v2 3/5] benchtests: Add a script to convert benchout string JSON to CSV Naohiro Tamura via Libc-alpha
2021-07-21  2:41   ` naohirot--- via Libc-alpha
2021-07-27 20:17   ` Joseph Myers
2021-07-29  1:56     ` naohirot--- via Libc-alpha
2021-07-29  4:42       ` Siddhesh Poyarekar
2021-07-30  7:05         ` naohirot--- via Libc-alpha
2021-07-31 10:47           ` Siddhesh Poyarekar
2021-07-20  6:36 ` [PATCH v2 4/5] benchtests: Remove redundant assert.h Naohiro Tamura via Libc-alpha
2021-07-20  6:37 ` [PATCH v2 5/5] benchtests: Fix validate_benchout.py exceptions Naohiro Tamura via Libc-alpha
2021-07-26  8:34 ` [PATCH] config: Remove HAVE_BUILTIN_MEMSET macro Naohiro Tamura via Libc-alpha
2021-07-26  8:48   ` naohirot--- via Libc-alpha
2021-07-26  8:49   ` Andreas Schwab
2021-07-26  9:42     ` naohirot--- via Libc-alpha
2021-07-26  9:51       ` Andreas Schwab
2021-07-26 13:16         ` naohirot--- via Libc-alpha
2021-07-26  8:35 ` [PATCH] benchtests: Add a script to merge two benchout string files Naohiro Tamura via Libc-alpha
2021-07-27 20:51   ` Joseph Myers
2021-07-30  7:04     ` naohirot--- via Libc-alpha

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