linux-kernel - Re: [PATCH 02/14] perf/bench: Default to all routines in 'perf bench mem'

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 19 Oct 2015 08:21:35 -0700
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	David Ahern <dsahern@...il.com>, Jiri Olsa <jolsa@...hat.com>,
	Hitoshi Mitake <mitake@....info.waseda.ac.jp>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 02/14] perf/bench: Default to all routines in 'perf bench mem'

On Mon, Oct 19, 2015 at 1:04 AM, Ingo Molnar <mingo@...nel.org> wrote:
>
>         triton:~> perf bench mem all
>         # Running mem/memcpy benchmark...
>         Routine default (Default memcpy() provided by glibc)
>                4.957170 GB/Sec (with prefault)
>         Routine x86-64-unrolled (unrolled memcpy() in arch/x86/lib/memcpy_64.S)
>                4.379204 GB/Sec (with prefault)
>         Routine x86-64-movsq (movsq-based memcpy() in arch/x86/lib/memcpy_64.S)
>                4.264465 GB/Sec (with prefault)
>         Routine x86-64-movsb (movsb-based memcpy() in arch/x86/lib/memcpy_64.S)
>                6.554111 GB/Sec (with prefault)

Is this skylake? And why are the numbers so low? Even on my laptop
(Haswell), I get ~21GB/s (when setting cpufreq to performance).

It's interesting that 'movsb' for you is so much better. It's been
promising before, and it *should* be able to do better than manual
copying, but it's not been that noticeable on the machines I've
tested. But I haven't ued Skylake or Broadwell yet.

cpufreq might be making a difference too. Maybe it's just ramping up
the CPU? Or is that really repeatable?

                     Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/