Date: Sun, 30 Sep 2001 14:06:32 -0700 From: "Charles Burns" <burnscharlesn@hotmail.com> To: questions@freebsd.org Subject: GCC 3.0 terrible for Athlon Message-ID: <F103TXLaWScrXhsL6qO0000bd60@hotmail.com>
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This may be old news, but http://www.cs.utk.edu/~rwhaley/ATLAS/gcc30.html describes some serious problems that GCC 3.0 has when using Athlon processors. Here's a clip: --------------- From the experiments described below, I think it is highly probable that there are two significant problems with gcc 3.0 on x86: The 3.0 fetch scheduler is optimized for Pentiums, to the very great detriment of Athlons. The scheduling algorithm used in the 2.9x series is much better for Athlons (2.96-80 has this problem as well). For ATLAS's kernel on Athlons, this problem causes an almost 50% drop in performance. 3.0's fpu stack handling is inferior to 2.9x's on all x86 platforms (2.96-80 does not have this problem, if you turn up optimization over that required in earlier releases). For ATLAS's kernel on any x86 (actually, confirmed for PIII & Athlon only), this problem causes a roughly 10% drop in performance. ---------------- Ouch! The performace figures shouldn't bee too different for BSD. Charles Burns _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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