On Tue, 5 Jul 2005 17:51:50 -0700 (PDT), Linus Torvalds <[email protected]> wrote:
>
>Btw, can you try this same thing (or at least a subset) with a large file
>on a filesystem? Does that show the same pattern, or is it always just the
>raw device?
>
Sure, take a while longer to vary by block size. One effect seems
to be wrong is interaction between /dev/hda and /dev/hdc in 'peetoo',
the IDE channels not independent?
write: time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
read: time dd of=/dev/null bs=1M if=/zeroes
summary 2.4.31-hf1 2.6.12.2
boxen \ time -> w r w r
--------------- ---- ---- ---- ----
menace 58.5 50 57 47.5
pooh 24 24 22.5 27
peetoo 33 20 26.5 22
(simultaneuous 57 37.5 52 38.5)
silly 54 24 49 25
tosh 30 19.5 27 19.5
filesystem: reiserfs 3.6, distro: slackware-10.1 + updates
hardware config, etc: http://scatter.mine.nu/test/
--Grant
the long story:
root@menace:~# uname -r
2.4.31-hf1
root@menace:~# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda3 1991992 1074516 917476 54% /
deltree:/home/share 2064256 1042968 1021288 51% /home/share
root@menace:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m57.830s
user 0m0.050s
sys 0m20.940s
root@menace:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m59.041s
user 0m0.030s
sys 0m21.780s
root@menace:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m49.963s
user 0m0.000s
sys 0m15.510s
- - -
root@menace:~# uname -r
2.6.12.2a
root@menace:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m57.199s
user 0m0.022s
sys 0m15.040s
root@menace:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m56.825s
user 0m0.024s
sys 0m14.893s
root@menace:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m47.560s
user 0m0.017s
sys 0m15.533s
root@menace:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m47.842s
user 0m0.012s
sys 0m15.647s
o o o
root@pooh:~# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda3 3084380 2018240 1066140 66% /
/dev/hda6 2056220 1049544 1006676 52% /usr/src
/dev/hda7 256996 34260 222736 14% /usr/local
/dev/hda8 256996 33896 223100 14% /home
/dev/hda14 20562536 32840 20529696 1% /home/pooh
deltree:/home/share 2064256 1042968 1021288 51% /home/share
root@pooh:~# uname -r
2.4.31-hf1
root@pooh:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m23.912s
user 0m0.010s
sys 0m19.820s
root@pooh:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m24.302s
user 0m0.020s
sys 0m16.760s
- - -
root@pooh:~# uname -r
2.6.12.2a
root@pooh:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m22.449s
user 0m0.017s
sys 0m13.576s
root@pooh:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m26.780s
user 0m0.010s
sys 0m13.398s
o o o
peetoo:~$ df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda3 2586348 1075652 1510696 42% /
/dev/hdc3 2586348 2044228 542120 80% /usr
/dev/hdc6 2586348 1217568 1368780 48% /usr/src
/dev/hda9 20562504 10821500 9741004 53% /home/install
/dev/hdc9 20562504 4329320 16233184 22% /home/public
/dev/hda10 41446344 39676256 1770088 96% /home/archive
deltree:/home/share 2064256 1042968 1021288 51% /home/share
peetoo:~$ uname -r
2.4.31-hf1
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m33.322s
user 0m0.000s
sys 0m13.650s
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m32.983s
user 0m0.010s
sys 0m13.740s
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/usr/zeroes; sync)
500+0 records in
500+0 records out
real 0m30.775s
user 0m0.000s
sys 0m13.600s
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/usr/zeroes; sync)
500+0 records in
500+0 records out
real 0m33.077s
user 0m0.010s
sys 0m13.740s
peetoo:~$ time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m18.877s
user 0m0.000s
sys 0m5.600s
peetoo:~$ time dd of=/dev/null bs=1M if=/usr/zeroes
500+0 records in
500+0 records out
real 0m21.413s
user 0m0.000s
sys 0m5.360s
peetoo:~$ time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m18.940s
user 0m0.000s
sys 0m5.390s
peetoo:~$ time dd of=/dev/null bs=1M if=/usr/zeroes
500+0 records in
500+0 records out
real 0m22.120s
user 0m0.000s
sys 0m5.520s
peetoo:~$ time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m36.991s
user 0m0.000s
sys 0m5.810s
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/usr/zeroes; sync)
500+0 records in
500+0 records out
real 0m57.718s
user 0m0.000s
sys 0m13.580s
simultaneous:
peetoo:~$ time dd of=/dev/null bs=1M if=/usr/zeroes
500+0 records in
500+0 records out
real 0m38.057s
user 0m0.010s
sys 0m5.790s
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m57.164s
user 0m0.020s
sys 0m13.660s
- - -
peetoo:~$ uname -r
2.6.12.2b
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m26.779s
user 0m0.017s
sys 0m5.634s
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/usr/zeroes; sync)
500+0 records in
500+0 records out
real 0m26.112s
user 0m0.017s
sys 0m5.358s
peetoo:~$ time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m21.630s
user 0m0.005s
sys 0m5.405s
peetoo:~$ time dd of=/dev/null bs=1M if=/usr/zeroes
500+0 records in
500+0 records out
real 0m22.489s
user 0m0.013s
sys 0m5.378s
simultaneous with other drive:
peetoo:~$ time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m38.149s
user 0m0.007s
sys 0m5.559s
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/usr/zeroes; sync)
500+0 records in
500+0 records out
real 0m52.272s
user 0m0.012s
sys 0m5.461s
- - -
second terminal:
peetoo:~$ time dd of=/dev/null bs=1M if=/usr/zeroes
500+0 records in
500+0 records out
real 0m38.998s
user 0m0.006s
sys 0m5.517s
peetoo:~$ time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m51.610s
user 0m0.018s
sys 0m5.470s
o o o
root@silly:~# uname -r
2.4.31-hf1
root@silly:~# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda3 3084380 755932 2328448 25% /
/dev/hda5 3084348 1168428 1915920 38% /usr/src
/dev/hda6 256996 39768 217228 16% /usr/local
/dev/hda7 514028 32864 481164 7% /home
deltree:/home/share 2064256 1042968 1021288 51% /home/share
root@silly:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m58.657s
user 0m0.020s
sys 0m16.810s
root@silly:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m50.276s
user 0m0.040s
sys 0m17.240s
root@silly:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m23.814s
user 0m0.010s
sys 0m8.470s
root@silly:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m23.834s
user 0m0.020s
sys 0m8.500s
- - -
root@silly:~# uname -r
2.6.12.2a
root@silly:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m49.564s
user 0m0.021s
sys 0m7.556s
root@silly:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m48.234s
user 0m0.016s
sys 0m7.466s
root@silly:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m24.900s
user 0m0.009s
sys 0m8.430s
root@silly:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m25.205s
user 0m0.015s
sys 0m8.394s
o o o
root@tosh:~# uname -r
2.4.31-hf1
root@tosh:~# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda3 4112508 2997808 1114700 73% /
/dev/hda6 124427 996 117007 1% /usr/local
/dev/hda7 124427 99 117904 1% /home
deltree:/home/share 2064256 1042968 1021288 51% /home/share
root@tosh:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m33.789s
user 0m0.040s
sys 0m9.430s
root@tosh:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m27.702s
user 0m0.000s
sys 0m9.940s
root@tosh:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m19.878s
user 0m0.000s
sys 0m4.510s
root@tosh:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m19.288s
user 0m0.000s
sys 0m4.580s
- - -
root@tosh:~# uname -r
2.6.12.2a
root@tosh:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m27.120s
user 0m0.010s
sys 0m4.937s
root@tosh:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync)
500+0 records in
500+0 records out
real 0m27.015s
user 0m0.010s
sys 0m4.844s
root@tosh:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m19.301s
user 0m0.006s
sys 0m4.558s
root@tosh:~# time dd of=/dev/null bs=1M if=/zeroes
500+0 records in
500+0 records out
real 0m19.513s
user 0m0.009s
sys 0m4.574s
o o o
end :)
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