On Tue, Jul 05 2005, Ondrej Zary wrote: > Jens Axboe wrote: > >On Tue, Jul 05 2005, Ondrej Zary wrote: > > > >>André Tomt wrote: > >> > >>>Al Boldi wrote: > >>> > >>> > >>>>Bartlomiej Zolnierkiewicz wrote: { > >>>> > >>>> > >>>>>>>On 7/4/05, Al Boldi <[EMAIL PROTECTED]> wrote: > >>>>>>>Hdparm -tT gives 38mb/s in 2.4.31 > >>>>>>>Cat /dev/hda > /dev/null gives 2% user 33% sys 65% idle > >>>>>>> > >>>>>>>Hdparm -tT gives 28mb/s in 2.6.12 > >>>>>>>Cat /dev/hda > /dev/null gives 2% user 25% sys 0% idle 73% IOWAIT > >>> > >>> > >>>The "hdparm doesn't get as high scores as in 2.4" is a old discussed to > >>>death "problem" on LKML. So far nobody has been able to show it affects > >>>anything but that pretty useless quasi-benchmark. > >>> > >> > >>No, it's not a problem with hdparm. hdparm only shows that there is > >>_really_ a problem: > >> > >>2.6.12 > >>[EMAIL PROTECTED]:/home/rainbow# time dd if=/dev/hda of=/dev/null bs=512 > >>count=1048576 > >>1048576+0 records in > >>1048576+0 records out > >> > >>real 0m32.339s > >>user 0m1.500s > >>sys 0m14.560s > >> > >>2.4.26 > >>[EMAIL PROTECTED]:/home/rainbow# time dd if=/dev/hda of=/dev/null bs=512 > >>count=1048576 > >>1048576+0 records in > >>1048576+0 records out > >> > >>real 0m23.858s > >>user 0m1.750s > >>sys 0m15.180s > > > > > >Perhaps some read-ahead bug. What happens if you use bs=128k for > >instance? > > > Nothing - it's still the same. > > [EMAIL PROTECTED]:/home/rainbow# time dd if=/dev/hda of=/dev/null bs=128k > count=4096 > 4096+0 records in > 4096+0 records out > > real 0m32.832s > user 0m0.040s > sys 0m15.670s
Can you post full dmesg of 2.4 and 2.6 kernel boot? What does hdparm -I/-i say for both kernels? -- Jens Axboe - 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/