Date: Thu, 12 Jul 2007 17:17:57 -0500 (CDT) From: "Sean C. Farley" <scf@FreeBSD.org> To: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no> Cc: freebsd-arch@FreeBSD.org Subject: Re: Assembly string functions in i386 libc Message-ID: <20070712170748.W8789@thor.farley.org> In-Reply-To: <86hco95lg8.fsf@dwp.des.no> References: <20070711134721.D2385@thor.farley.org> <20070711221338.GC20178@turion.vk2pj.dyndns.org> <200707112221.l6BML722062857@apollo.backplane.com> <20070711183217.C2385@thor.farley.org> <86lkdl5osc.fsf@dwp.des.no> <20070712161200.I8789@thor.farley.org> <86hco95lg8.fsf@dwp.des.no>
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This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --0-1811604476-1184278677=:8789 Content-Type: TEXT/PLAIN; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE On Fri, 13 Jul 2007, Dag-Erling Sm=F8rgrav wrote: > "Sean C. Farley" <scf@FreeBSD.org> writes: >> On Thu, 12 Jul 2007, Dag-Erling Sm=F8rgrav wrote: >>> The first rule of optimization is: don't do it. >>> The second rule of optimization is: don't do it yet. >>> The third rule of optimization is: don't optimize what you haven't >>> measured. >> I am a rule breaker at least for the first two. :) I tried to >> follow the third rule. >> >>> Can you show us an actual application that spends a significant part >>> of its run time in strlen()? >> My test program that loops over strlen(). > > So the answer is no, and you don't understand the third rule which you > claim to follow. I never claimed to succeed; I only tried. The two types of tests I can think would be useful were execution of strlen() by itself and within a common program. I had thought I had tested the first type of test. The second one I did later with different versions of strlen() using diff. What types of tests would have been better? I know about gprof for finding where a specific program is spending its time, but I was focusing on the strlen() call. Also, having two different versions in the source tree is still puzzling me. Sean --=20 scf@FreeBSD.org --0-1811604476-1184278677=:8789--
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