Re: confused about performance
Leopold Palomo-Avellaneda wrote:
A Dijous 14 Juny 2007 16:32, Lennart Sorensen va escriure:
Now I just tried a small stupid test here:
I have a zip file that is 61592222 bytes. I tried running
'time tar cvzf test.tgz my.zip' on both 32 and 64 bit on an Athlon 64 3500+
running a 64bit kernel with 1GB ram.
According to time, it takes 0m3.776s of user time (so not counting
system calls) on 64bit, and 0m4.556s on 32bit. That indicates tar/gzip
runs 20% faster on 64bit than 32bit at least when the kernel is 64bit
and run on the same machine. I ran them a few times each to make sure
caching and such didn't affect them. Maybe your test method wasn't
correct or the two systems aren't as identical as you think.
FWIW, I also observe that 64 bits application (Debian/Etch) are running faster than 32 bits application on the same
hardware (actually I am testing on a DualCore2 (Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz, 4096 KB) with AMD64 kernel 2Gb
RAM (enough to keep a 300Mb file in cache) and a chrooted 32 bits subsystem
For a 300Mb file (gotten from /dev/urandom with dd):
in 64 bits the best time (of 5 runs) for wc is
1228486 6931475 314572800 /tmp/bigfile2
wc /tmp/bigfile2 3.36s user 0.14s system 99% cpu 3.500 total
The best time in 32 bits mode is (chrooted on same hardware)
1228486 6931475 314572800 /tmp/bigfile2
wc /tmp/bigfile2 4.14s user 0.10s system 99% cpu 4.251 total
For compression with bzip2 the best time in 64 bits is
bzip2 -c /tmp/bigfile2 > /dev/null 74.43s user 0.13s system 99% cpu 1:14.58 total
and in 32 bits
bzip2 -c /tmp/bigfile2 > /dev/null 81.68s user 0.15s system 99% cpu 1:21.86 total
For the md5 checksum, best time in 64 bits is
2c461881e5d354dc8f304173fb915ad7 /tmp/bigfile2
md5sum /tmp/bigfile2 0.73s user 0.10s system 100% cpu 0.829 total
and in 32 bits
2c461881e5d354dc8f304173fb915ad7 /tmp/bigfile2
md5sum /tmp/bigfile2 0.90s user 0.12s system 99% cpu 1.029 total
As you can see, running in 64 bits is always a win.
--
Basile STARYNKEVITCH http://starynkevitch.net/Basile/
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