From: "Zack Weinberg" <zack@codesourcery.com>
To: Daniel Jacobowitz <drow@mvista.com>
Cc: Ulrich Drepper <drepper@redhat.com>,
Richard Henderson <rth@redhat.com>, Andreas Jaeger <aj@suse.de>,
libc-alpha@sources.redhat.com, linux-gcc@vger.kernel.org,
gcc@gcc.gnu.org
Subject: Re: i386 inline-asm string functions - some questions
Date: Mon, 29 Dec 2003 11:09:14 -0800 [thread overview]
Message-ID: <8765fzjvad.fsf@egil.codesourcery.com> (raw)
In-Reply-To: <20031229233708.F6728@zzz.ward.six> (Denis Zaitsev's message of "Mon, 29 Dec 2003 23:37:08 +0500")
Denis Zaitsev <zzz@anda.ru> writes:
> On Mon, Dec 29, 2003 at 12:31:52AM -0500, Daniel Jacobowitz wrote:
>> Funny, I conducted this experiment last week and found quite the
>> opposite. Compiling the demangler and a smallish yacc parser
>> with -D__NO_STRING_INLINES cost about 20% in runtime.
>
> -D__NO_STRING_INLINES just puts the inlining off. But nobody here
> tells about the inline/noinline comparing. Of course, inlining is
> better at speed. The comparison is doing between some versions of the
> inlining.
No. There is no "of course" here. If your inlined functions blow out
the instruction cache, it may wind up being a net lose. Same if the
out-of-line memcpy takes several more instructions to set up but makes
damn sure to do aligned memory accesses (full-bus-width loads,
nontemporal store, prefetches, etc etc etc), whereas the inline one
doesn't.
zw
next prev parent reply other threads:[~2003-12-29 19:09 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-25 0:20 i386 inline-asm string functions - some questions Denis Zaitsev
2003-12-25 0:38 ` Richard Henderson
2003-12-25 1:15 ` Denis Zaitsev
2003-12-25 1:21 ` Zack Weinberg
2003-12-25 1:45 ` Denis Zaitsev
2003-12-26 3:40 ` Zack Weinberg
2003-12-27 4:58 ` Richard Henderson
2003-12-27 10:24 ` Zack Weinberg
2003-12-27 11:35 ` Denis Zaitsev
2003-12-27 18:38 ` Zack Weinberg
2003-12-28 20:58 ` Denis Zaitsev
2003-12-29 2:22 ` Zack Weinberg
2003-12-29 2:44 ` Denis Zaitsev
2003-12-29 2:46 ` Zack Weinberg
2003-12-29 2:53 ` Denis Zaitsev
2003-12-29 3:35 ` Ulrich Drepper
2003-12-29 3:54 ` Andrew Pinski
2003-12-29 6:57 ` Jakub Jelinek
2003-12-29 3:56 ` Zack Weinberg
2003-12-29 5:31 ` Daniel Jacobowitz
2003-12-29 5:55 ` Zack Weinberg
2003-12-29 18:37 ` Denis Zaitsev
2003-12-29 19:09 ` Zack Weinberg [this message]
2003-12-29 19:31 ` Denis Zaitsev
2003-12-29 19:37 ` Denis Zaitsev
2003-12-29 18:51 ` Denis Zaitsev
2003-12-29 19:15 ` Zack Weinberg
2003-12-27 10:52 ` Denis Zaitsev
[not found] ` <20031225060850.C7419@zzz.ward.six>
[not found] ` <20031225012711.GD13447@redhat.com>
2003-12-25 1:38 ` Denis Zaitsev
2003-12-25 1:53 ` Richard Henderson
2003-12-25 2:08 ` Denis Zaitsev
2003-12-25 0:39 ` Roland McGrath
2003-12-25 1:13 ` Denis Zaitsev
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