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: [EMAIL PROTECTED]:~# uname -r 2.4.31-hf1 [EMAIL PROTECTED]:~# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/hda3 1991992 1074516 917476 54% / deltree:/home/share 2064256 1042968 1021288 51% /home/share [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 - - - [EMAIL PROTECTED]:~# uname -r 2.6.12.2a [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# uname -r 2.4.31-hf1 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 - - - [EMAIL PROTECTED]:~# uname -r 2.6.12.2a [EMAIL PROTECTED]:~# time $(dd if=/dev/zero bs=1M count=500 of=/zeroes; sync) 500+0 records in 500+0 records out real 0m22.449s user 0m0.017s sys 0m13.576s [EMAIL PROTECTED]:~# time dd of=/dev/null bs=1M if=/zeroes 500+0 records in 500+0 records out real 0m26.780s user 0m0.010s sys 0m13.398s o o o peetoo:~$ 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 [EMAIL PROTECTED]:~# uname -r 2.4.31-hf1 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 - - - [EMAIL PROTECTED]:~# uname -r 2.6.12.2a [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# uname -r 2.4.31-hf1 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 - - - [EMAIL PROTECTED]:~# uname -r 2.6.12.2a [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 [EMAIL PROTECTED]:~# 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 :) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
