Date: Wed, 14 Dec 2005 20:37:49 -0500 From: Chuck Swiger <cswiger@mac.com> To: Gary Kline <kline@tao.thought.org> Cc: freebsd-questions@freebsd.org, Kent Stewart <kstewart@owt.com> Subject: Re: fquestions Message-ID: <43A0C8ED.4090209@mac.com> In-Reply-To: <20051215005519.GA44946@thought.org> References: <20051214171014.GB37495@thought.org> <7088318B-3141-44E6-9F50-CB51F6CAE501@mac.com> <20051214211749.GJ41870@thought.org> <200512141342.22051.kstewart@owt.com> <20051215005519.GA44946@thought.org>
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Gary Kline wrote: > On Wed, Dec 14, 2005 at 01:42:21PM -0800, Kent Stewart wrote: [ ... ] > Does it make any sense to use O3 when compiling stuff, > when stuff includes world/kernel/drivers? Does upping the > optimization make any significant difference in system > performance, in other words? Kent? Anybody? No. You are likely to vastly increase the amount of time it takes to compile the system without gaining any performance that's noticable. The system generally shouldn't be spending a lot of CPU in the kernel, anyway, compared with the amount of time running user-mode code. (Firewalls and routers are a significant exception, however.) If you want your system to perform better, benchmark the work it's actually doing, and then tune from there. Spending lots of time to optimize a part of the system that is already pretty efficient isn't going to do much, whereas solving the bottleneck will make a useful difference. -- -Chuck
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