From: Andrew Morton <akpm@linux-foundation.org>
To: Matteo Croce <mcroce@linux.microsoft.com>
Cc: linux-kernel@vger.kernel.org, Nick Kossifidis <mick@ics.forth.gr>,
Guo Ren <guoren@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
David Laight <David.Laight@aculab.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Emil Renner Berthing <kernel@esmil.dk>,
Drew Fustini <drew@beagleboard.org>,
linux-arch@vger.kernel.org,
Nick Desaulniers <ndesaulniers@google.com>,
linux-riscv@lists.infradead.org
Subject: Re: [PATCH v2 0/3] lib/string: optimized mem* functions
Date: Sat, 10 Jul 2021 14:31:09 -0700 [thread overview]
Message-ID: <20210710143109.fd5062902ef4d5d59e83f5bb@linux-foundation.org> (raw)
In-Reply-To: <20210702123153.14093-1-mcroce@linux.microsoft.com>
On Fri, 2 Jul 2021 14:31:50 +0200 Matteo Croce <mcroce@linux.microsoft.com> wrote:
> From: Matteo Croce <mcroce@microsoft.com>
>
> Rewrite the generic mem{cpy,move,set} so that memory is accessed with
> the widest size possible, but without doing unaligned accesses.
>
> This was originally posted as C string functions for RISC-V[1], but as
> there was no specific RISC-V code, it was proposed for the generic
> lib/string.c implementation.
>
> Tested on RISC-V and on x86_64 by undefining __HAVE_ARCH_MEM{CPY,SET,MOVE}
> and HAVE_EFFICIENT_UNALIGNED_ACCESS.
>
> These are the performances of memcpy() and memset() of a RISC-V machine
> on a 32 mbyte buffer:
>
> memcpy:
> original aligned: 75 Mb/s
> original unaligned: 75 Mb/s
> new aligned: 114 Mb/s
> new unaligned: 107 Mb/s
>
> memset:
> original aligned: 140 Mb/s
> original unaligned: 140 Mb/s
> new aligned: 241 Mb/s
> new unaligned: 241 Mb/s
Did you record the x86_64 performance?
Which other architectures are affected by this change?
next prev parent reply other threads:[~2021-07-10 21:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-02 12:31 [PATCH v2 0/3] lib/string: optimized mem* functions Matteo Croce
2021-07-02 12:31 ` [PATCH v2 1/3] lib/string: optimized memcpy Matteo Croce
2021-07-02 14:37 ` Ben Dooks
2021-07-02 14:44 ` Matteo Croce
2021-07-02 12:31 ` [PATCH v2 2/3] lib/string: optimized memmove Matteo Croce
2021-07-02 12:31 ` [PATCH v2 3/3] lib/string: optimized memset Matteo Croce
2021-07-10 21:31 ` Andrew Morton [this message]
2021-07-10 23:07 ` [PATCH v2 0/3] lib/string: optimized mem* functions Matteo Croce
2021-07-12 8:15 ` David Laight
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