Date: Wed, 03 Apr 2002 09:14:42 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Jeroen Ruigrok/asmodai <asmodai@wxs.nl> Cc: Kenneth Culver <culverk@alpha.yumyumyum.org>, Dag-Erling Smorgrav <des@ofug.org>, Matthew Dillon <dillon@apollo.backplane.com>, Mike Barcroft <mike@FreeBSD.org>, "M. Warner Losh" <imp@village.org>, jake@locore.ca, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/i386/i386 critical.c src/sys/i386/include cpufunc.h critical.h src/sys/i386/isa apic_vector.s icu_vector.s src/sys/kern kern_fork.c kern_proc.c kern_switch.c src/sys/alpha/alph Message-ID: <48244.1017818082@critter.freebsd.dk> In-Reply-To: Your message of "Wed, 03 Apr 2002 07:25:04 %2B0200." <20020403052504.GJ78613@daemon.ninth-circle.org>
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In message <20020403052504.GJ78613@daemon.ninth-circle.org>, Jeroen Ruigrok/asm odai writes: >-On [20020402 23:45], Kenneth Culver (culverk@alpha.yumyumyum.org) wrote: >>> Using spaces instead of tabs, especially in headers, has a noticeable >>> (negative) impact on compilation speed. We could speed buildworld up >>> significantly by stripping comments and superfluous whitespace from the >>> headers we install in /usr/obj. >> >>This I didn't know, but it makes sense. > >It does, since the first production rule in any grammar of a language is >often to match whitespace. [Since it occurs most often, placing it at the >top makes a lot of sense.] > >The parser has to iterate 8 times instead of 1 time for a single tab >character. > >How much gain you really get I don't know, that would need to be timed. My buildworld time increased about 2 seconds after running /usr/src through "pr -e -t". Disk usage on the other hand shot up by 30M. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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