Date: Fri, 27 Oct 2000 12:48:27 -0500 From: "Jeffrey J. Mountin" <jeff-ml@mountin.net> To: Donn Miller <dmmiller@cvzoom.net> Cc: stable@FreeBSD.ORG Subject: Re: "Malloc type lacks magic" show-stopper solved Message-ID: <4.3.2.20001027114057.00b91100@207.227.119.2> In-Reply-To: <39F91FA9.F3FC1B22@cvzoom.net> References: <20001026222017.A9391@dragon.nuxi.com> <Pine.LNX.4.21.0010271856080.16125-100000@vimfuego.saarinen.org> <20001026231134.D9391@dragon.nuxi.com> <20001026231338.E9391@dragon.nuxi.com>
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At 02:24 AM 10/27/00 -0400, Donn Miller wrote: >I wouldn't do that. I'd just hard-code -O in the Makefile used to >compile the kernel. Or, you could put a perl or sed script in >/sys/i386/* that does something like s/-O[12s]/-O/, so that any flags >specified, such as -O2, -O3, or -Os are converted to -O. I'd keep the >ability to do something like -march=ARCH, though, as that doesn't cause >the headaches that -O3 et. al. do. What is interesting is that -march will produce a slightly larger binary than -mcpu. Would expect the opposite, since the code is compiled to run *only* on one CPU class with -march, rather than just a scheduling change. Also should clarify in my previous message that using anything other than -O (ie -Os or => -O2) with -march tends to make compiling problematic. Related to that is the compile time for buildword is about 15% slower with -O2, so those going for the "macho" compilier flags might *think* things are faster (only a few have posted tests results), but their build times are guaranteed to be significantly slower. Anyone doing any testing should check the binary's size, compile time, and of course performance. Checking back the order of variance is compile time, size, and performance. While all the talk (or speculation) hits on my curiosity, there seems little to be gained overall by optimization changes, unless they are applied to a specific program. Even then I can only generalize, since there is little empirical data. ISTR some testing by PHK, but think it related to egcs vs gcc and another (same?) using bzip for testing. Jeff Mountin - jeff@mountin.net Systems/Network Administrator FreeBSD - the power to serve To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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