Date: Thu, 26 May 2005 10:13:35 +1000 From: Michael VInce <mv@roq.com> To: Nicolas Blais <nb_root@videotron.ca> Cc: freebsd-amd64@freebsd.org Subject: Re: amd64 optimized gcc? Message-ID: <429514AF.5000306@roq.com> In-Reply-To: <200505251317.22128.nb_root@videotron.ca> References: <200505251317.22128.nb_root@videotron.ca>
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Interesting. I have been playing with GCC optimizations my self latterly and have been wondering how much it helps, haven't done any benchmarks though. I some times wonder if the GCC people are doing good working with optimization flags. I recently lost my hard drive on my ASUS A4K (AMD64) laptop, so bought a new 16meg cache 80gig Toshiba hard drive for it, while I wait for warranty to come through on my old one. I did a buildworld under 'CPUTYPE=athlon64' in make.conf and 'CFLAGS= -O2 -pipe -funroll-loops' for the the kernel. I also used both to build all my ports including xorg and KDE. All this combined has made my laptop feel a lot faster. After I load up openoffice2 (via Linux emu) once I can fully reopen a xls file in about 1.5 seconds, I believe the HD cache must be playing a bit part in that. Mike Nicolas Blais wrote: >I am developping a software that follows a random()-dependant algorithm which >is extremely cpu intensif. >I decided to run on different platforms to see how it performed based on cpu >and os (in a way of benchmarking) and I'm surprised by the numbers: > >Reference times for benchmark (5e+07 run of the algorithm): > >(FreeBSD/i386) Venice (S939, 512K L2 cache) Athlon64 3000 overclocked @ 2655 >Mhz : 78.3072 s (638511 r/s) > Note: Cool 'n' Quiet! Disabled in BIOS. > Note: 1 G RAM > >(FreeBSD/amd64) Venice (S939, 512K L2 cache) Athlon64 3000 overclocked @ 2655 >Mhz : 71.2521 s (701732 r/s) > Note: Cool 'n' Quiet! Disabled in BIOS. > Note: 1 G RAM > >(Knoppix/i386) Clawhammer (S747, 1MB L2 cache) Athlon64 3200 @ 2000 Mhz : >133.858 s (373325 r/s) > Note: Compaq R3240CA Laptop, Cool 'n' Quiet! forced by BIOS. > Note: 512 M RAM > >(FreeBSD/amd64) Clawhammer (S747, 1MB L2 cache) Athlon64 3200 @ 2000 Mhz : >47.2754 s (1057630 r/s) > Note: Compaq R3240CA Laptop, Cool 'n' Quiet! forced by BIOS. > sysctl hw.acpi.cpu.px_control=-1 > Note: 512 M RAM > >(FreeBSD/i386) Pentium II @ 233 Mhz : 538.136 s (92913.3 r/s) > Note: 192 M RAM > >Not surprising is the Pentium II :). What is surprising is that amd64 FreeBSD >seems to execute code faster than i386 FreeBSD, so I'm wondering if gcc >(amd64) really optimizes code for the cpu. If it is, I would probably move my >httpd server to amd64... > >Also, maybe less surprising is that Knoppix sucks running the algorithm for >some reason and that L2 cache really is a big factor (my Laptop outperforms >my heavily overclocked box). > >Any comments? > >
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