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Date:      Wed, 25 May 2005 13:17:15 -0400
From:      Nicolas Blais <nb_root@videotron.ca>
To:        freebsd-amd64@freebsd.org
Subject:   amd64 optimized gcc?
Message-ID:  <200505251317.22128.nb_root@videotron.ca>

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I am developping a software that follows a random()-dependant algorithm whi=
ch=20
is extremely cpu intensif.=20
I decided to run on different platforms to see how it performed based on cp=
u=20
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 @ 26=
55=20
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 @ 2=
655=20
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 :=
=20
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 :=
=20
47.2754 s (1057630 r/s)
                Note: Compaq R3240CA Laptop, Cool 'n' Quiet! forced by BIOS.
                sysctl hw.acpi.cpu.px_control=3D-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 Free=
BSD=20
seems to execute code faster than i386 FreeBSD, so I'm wondering if gcc=20
(amd64) really optimizes code for the cpu. If it is, I would probably move =
my=20
httpd server to amd64...

Also, maybe less surprising is that Knoppix sucks running the algorithm for=
=20
some reason and that L2 cache really is a big factor (my Laptop outperforms=
=20
my heavily overclocked box).

Any comments?
=2D-=20
=46reeBSD 6.0-CURRENT #2: Sun May 22 11:29:47 EDT 2005    =20
nicblais@clk01a:/usr/obj/usr/src/sys/CLK01A=20
PGP? : http://66.130.198.54:8081/security/nb_root.asc

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