From: Andre Renaud <andre@bluewatersys.com>
To: Andre Renaud <andre@bluewatersys.com>
Cc: musl@lists.openwall.com
Subject: Re: Thinking about release
Date: Thu, 11 Jul 2013 10:44:16 +1200 [thread overview]
Message-ID: <CAPfzE3YDFjqHxRaZFeiy0CvbYWYGKzgDGEp-71xSz-03GhNTxw@mail.gmail.com> (raw)
In-Reply-To: <CAPfzE3ZsMpC9d4VDZyHabhKOffOQW0dnG7Nwpm8EqVBLUXNZKg@mail.gmail.com>
> This results in 95MB/s on my platform (up from 65MB/s for the existing
> memcpy.c, and down from 105MB/s with the asm optimised version). It is
> essentially identically readable to the existing memcpy.c. I'm not
> really famiilar with any other cpu architectures, so I'm not sure if
> this would improve, or hurt, performance on other platforms.
Reviewing the assembler that is produced, it appears that GCC will
never generate an ldm/stm instruction (load/store multiple) that reads
into more than 4 registers, where as the optimised assembler does them
that read 8 (ie: 8 * 32bit reads in a single instruction). I've tried
various tricks/optimisations with the C code, and can't convince GCC
to do more than 4. I assume that this is probably where the remaining
10MB/s is between these two variants.
Rich - do you have any comments on whether either the C or assembler
variants of memcpy might be suitable for inclusion in musl?
Regards,
Andre
next prev parent reply other threads:[~2013-07-10 22:44 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-13 1:25 Rich Felker
2013-06-13 1:33 ` Andre Renaud
2013-06-13 1:43 ` Rich Felker
2013-07-09 5:06 ` Andre Renaud
2013-07-09 5:37 ` Rich Felker
2013-07-09 6:24 ` Harald Becker
2013-07-09 21:28 ` Andre Renaud
2013-07-09 22:26 ` Andre Renaud
2013-07-10 6:42 ` Jens Gustedt
2013-07-10 7:50 ` Rich Felker
2013-07-10 22:44 ` Andre Renaud [this message]
2013-07-11 3:37 ` Rich Felker
2013-07-11 4:04 ` Andre Renaud
2013-07-11 5:10 ` Andre Renaud
2013-07-11 12:46 ` Rich Felker
2013-07-11 22:34 ` Andre Renaud
2013-07-12 3:16 ` Rich Felker
2013-07-12 3:36 ` Andre Renaud
2013-07-12 4:16 ` Rich Felker
2013-07-24 1:34 ` Andre Renaud
2013-07-24 3:48 ` Rich Felker
2013-07-24 4:40 ` Andre Renaud
2013-07-28 8:09 ` Rich Felker
2013-07-11 5:27 ` Daniel Cegiełka
2013-07-11 12:49 ` Rich Felker
2013-07-15 4:25 ` Rob Landley
2013-07-10 19:42 ` Rich Felker
2013-07-14 6:37 ` Rob Landley
2013-07-11 4:30 ` Strake
2013-07-11 4:33 ` Rich Felker
2013-07-10 19:38 ` Rob Landley
2013-07-10 20:34 ` Andre Renaud
2013-07-10 20:49 ` Nathan McSween
2013-07-10 21:01 ` Rich Felker
2013-06-13 15:46 ` Isaac
2013-06-26 1:44 ` Rich Felker
2013-06-26 10:19 ` Szabolcs Nagy
2013-06-26 14:21 ` Rich Felker
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