From: Andi Kleen <andi@firstfloor.org>
To: "Yu, Fenghua" <fenghua.yu@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
H Peter Anvin <hpa@zytor.com>,
"Mallick, Asit K" <asit.k.mallick@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Avi Kivity <avi@redhat.com>,
Arjan van de Ven <arjan@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 9/9] x86/lib/memset_64.S: Optimize memset by enhanced REP MOVSB/STOSB
Date: Wed, 18 May 2011 20:39:13 +0200 [thread overview]
Message-ID: <20110518183913.GA12317@one.firstfloor.org> (raw)
In-Reply-To: <493994B35A117E4F832F97C4719C4C04011505C7DC@orsmsx505.amr.corp.intel.com>
> I use gcc 4.3.2 installed by FC10 to build kernel with defconfig. Only memcpy is built with gcc builtin and inline memcpy. All of others (i.e. memset, clear_page, memmove, and copy_user) call the kernel lib.
>
> It's easy to check this by disassembling kernel binary.
gcc has a complex set of heuristics. For example if it cannot decide
the length or the alignment it calls the kernel code. Otherwise
it inlines.
So just looking at a few examples won't give you the whole picture.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2011-05-18 18:39 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-17 22:29 [PATCH 0/9] Optimize string operations by enhanced REP MOVSB/STOSB Fenghua Yu
2011-05-17 22:29 ` [PATCH 1/9] x86, cpu: Enable enhanced REP MOVSB/STOSB feature Fenghua Yu
2011-05-17 23:13 ` [tip:x86/cpufeature] x86, cpufeature: Add CPU feature bit for enhanced REP MOVSB/STOSB tip-bot for Fenghua Yu
2011-05-17 22:29 ` [PATCH 2/9] x86/kernel/cpu/intel.c: Initialize Enhanced REP MOVSB/STOSBenhanced Fenghua Yu
2011-05-18 2:46 ` Andi Kleen
2011-05-18 3:47 ` H. Peter Anvin
2011-05-18 20:40 ` [tip:perf/core] x86, mem, intel: Initialize Enhanced REP MOVSB/STOSB tip-bot for Fenghua Yu
2011-05-17 22:29 ` [PATCH 3/9] x86/kernel/alternative.c: Add comment for applying alternatives order Fenghua Yu
2011-05-18 20:40 ` [tip:perf/core] x86, alternative, doc: " tip-bot for Fenghua Yu
2011-05-17 22:29 ` [PATCH 4/9] x86, alternative-asm.h: Add altinstruction_entry macro Fenghua Yu
2011-05-18 20:41 ` [tip:perf/core] x86, alternative: " tip-bot for Fenghua Yu
2011-05-17 22:29 ` [PATCH 5/9] x86/lib/clear_page_64.S: Support clear_page() with enhanced REP MOVSB/STOSB Fenghua Yu
2011-05-18 20:41 ` [tip:perf/core] x86, mem: clear_page_64.S: " tip-bot for Fenghua Yu
2011-05-17 22:29 ` [PATCH 6/9] x86/lib/copy_user_64.S: Support copy_to_user/copy_from_user by " Fenghua Yu
2011-05-18 20:42 ` [tip:perf/core] x86, mem: copy_user_64.S: Support copy_to/from_user " tip-bot for Fenghua Yu
2011-05-17 22:29 ` [PATCH 7/9] x86/lib/memcpy_64.S: Optimize memcpy " Fenghua Yu
2011-05-18 6:35 ` Ingo Molnar
2011-05-18 19:04 ` Yu, Fenghua
2011-05-18 20:42 ` [tip:perf/core] x86, mem: memcpy_64.S: " tip-bot for Fenghua Yu
2011-05-17 22:29 ` [PATCH 8/9] x86/lib/memmove_64.S: Optimize memmove " Fenghua Yu
2011-05-18 20:43 ` [tip:perf/core] x86, mem: memmove_64.S: " tip-bot for Fenghua Yu
2011-05-17 22:29 ` [PATCH 9/9] x86/lib/memset_64.S: Optimize memset " Fenghua Yu
2011-05-18 2:57 ` Andi Kleen
2011-05-18 3:09 ` Yu, Fenghua
2011-05-18 4:05 ` Andi Kleen
2011-05-18 18:33 ` Yu, Fenghua
2011-05-18 18:39 ` Andi Kleen [this message]
2011-05-18 18:47 ` Ingo Molnar
2011-05-18 18:49 ` Yu, Fenghua
2011-05-18 20:43 ` [tip:perf/core] x86, mem: memset_64.S: " tip-bot for Fenghua Yu
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