Date: Mon, 6 Nov 2000 14:38:07 +0200 (IST) From: Roman Shterenzon <roman@harmonic.co.il> To: Randell Jesup <rjesup@wgate.com> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: "Malloc type lacks magic" show-stopper solved Message-ID: <Pine.LNX.4.10.10011061432050.24920-100000@shark.harmonic.co.il> In-Reply-To: <ybubsvyfhze.fsf@jesup.eng.tvol.net.jesup.eng.tvol.net>
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On 2 Nov 2000, Randell Jesup wrote: > Gerald Pfeifer <pfeifer@dbai.tuwien.ac.at> writes: > >David O'Brien wrote: > >> Forgot to mention. I'm considering removing the ability to do -O2 and > >> -O3 from the system C compiler again.... people are just proving over > >> and over how much they want to shoot their foot off. > > > >Please don't. We are already seeing enough problems due to differences > >between FSF GCC and FreeBSD's patched version. Please let's reduce those > >differences, not introduce anything further. > > Removing -O2 and -O3 from userland would be a Very Bad Thing, and > would cause us considerable consternation. Proper use of -O2, -O3, and > various -f's and -m's can get us 10's of % on some heavily compute-bound > code. This translates to considerable differences in $$$ in hardware. Do you have any specific examples? I, myself tried to compile some applications using -O vs. -O2 and even having -march=pentium , -march=k6 (I've K6-2) and tried to benchmark the resulting binaries. The results were quite similar, and the differences could have been blaimed on the 2nd level cache. I haven't found any "considerable differences", so I stick with -O . This wasn't true for 2.7.2.3 I think, since -O2 there produced faster binary than -O (I tested it on 3.4-RELEASE once). I don't remember -O3 producing ever faster code for me anyway. It just produced larger binary, probably filling delayed branch slots or whatever it is in Pentium :) (Don't comment on this one, I'm just kidding). --Roman Shterenzon, UNIX System Administrator and Consultant [ Xpert UNIX Systems Ltd., Herzlia, Israel. Tel: +972-9-9522361 ] To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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