Date: Sat, 13 May 2006 07:29:30 -0500 From: "Matthew D. Fuller" <fullermd@over-yonder.net> To: Jonathan Noack <noackjr@alumni.rice.edu> Cc: Dmitry Pryanishnikov <dmitry@atlantis.dp.ua>, freebsd-stable@FreeBSD.org, Kris Kennaway <kris@obsecurity.org> Subject: Re: RELENG_4 -> 5 -> 6: significant performance regression Message-ID: <20060513122930.GD3874@over-yonder.net> In-Reply-To: <4465843E.9070108@alumni.rice.edu> References: <20060427160536.M96305@atlantis.atlantis.dp.ua> <20060427181226.GA66431@xor.obsecurity.org> <20060428122448.K57436@atlantis.atlantis.dp.ua> <20060428182818.GA10410@xor.obsecurity.org> <20060512161836.R75964@atlantis.atlantis.dp.ua> <20060513020051.GB18438@xor.obsecurity.org> <20060513084236.W74146@atlantis.atlantis.dp.ua> <4465843E.9070108@alumni.rice.edu>
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On Sat, May 13, 2006 at 03:01:18AM -0400 I heard the voice of Jonathan Noack, and lo! it spake thus: > > Have you tried putting I586_CPU in there? See > http://lists.freebsd.org/pipermail/freebsd-stable/2005-December/020696.html. As Peter Jeremy mentioned in <http://lists.freebsd.org/pipermail/freebsd-stable/2005-December/020731.html>, the primary suspect (optimized copy/zero routines) would never happen except on a real 586 CPU, and is totally disabled anyway. See sys/i386/isa/npx.c line 424-437 (line numbers from rev 1.163, salt to taste): #ifdef I586_CPU_XXX if (cpu_class == CPUCLASS_586 && npx_ex16 && npx_exists && [...] The #ifdef will never match, and even if it did, the if() would never kick in unless the CPU was actually a 586. The #ifdef has been disabled since rev 1.95 (2001/04/13). (This isn't to say that there isn't something else hiding somewhere that I686_CPU doesn't enable that it should, but just nipping another round of the copy routine discussion in the bud...) -- Matthew Fuller (MF4839) | fullermd@over-yonder.net Systems/Network Administrator | http://www.over-yonder.net/~fullermd/ On the Internet, nobody can hear you scream.
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