Date: Wed, 13 May 2015 12:47:15 -0600 From: Ian Lepore <ian@freebsd.org> To: John-Mark Gurney <jmg@funkthat.com> Cc: Adrian Chadd <adrian@freebsd.org>, Hans Petter Selasky <hps@selasky.org>, David Chisnall <theraven@freebsd.org>, Poul-Henning Kamp <phk@phk.freebsd.dk>, Baptiste Daroussin <bapt@freebsd.org>, "current@freebsd.org" <current@freebsd.org> Subject: Re: Increase BUFSIZ to 8192 Message-ID: <1431542835.1221.30.camel@freebsd.org> In-Reply-To: <20150513181347.GM37063@funkthat.com> References: <20150511230635.GA46991@ivaldir.etoilebsd.net> <20150512032307.GP37063@funkthat.com> <14994.1431412293@critter.freebsd.dk> <20150513080342.GE37063@funkthat.com> <A1224018-7540-4C76-91EF-AEA2655E49A8@FreeBSD.org> <55530CC3.1090204@selasky.org> <1431528249.1221.15.camel@freebsd.org> <CAJ-VmonL9mT4JLqfSefKYiwv5-ecLkx9RZ5=kXt__%2Bs9iO4%2B9Q@mail.gmail.com> <20150513181347.GM37063@funkthat.com>
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On Wed, 2015-05-13 at 11:13 -0700, John-Mark Gurney wrote: > Adrian Chadd wrote this message on Wed, May 13, 2015 at 08:34 -0700: > > The reason I ask about "why is it faster?" is because for embedded-y > > things with low RAM we may not want that to happen due to memory > > constraints. However, we may actually want to do some form of > > autotuning on some platforms. > > If you're already running a program, the difference between 1k and > 8k isn't significant... I'll give you 64k can be significant for > embedded-y platforms... But this goes back to the, we need a global > knob saying I want low memory usage, and I am willing to pay for it > in performance... > It is NOT just a difference of 1K vs 8K. It's that much times however many BUFSIZ-sized things a program has allocated at once. It's where they are allocated. As I've already pointed out, BUFSIZ appears in the base code over 2000 times. Where is the analysis of the impact an 8x change is going to have on all those uses? -- Ian
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