cliff white wrote: >On Tue, 28 Oct 2003 05:52:45 +0800 >Michael Frank wrote: > > >>To my surprise 2.6 - which used to do better then 2.4 - does no longer >>handle these test that well. >> >>Generally, IDE IO throughput is _very_ uneven and IO _stops_ at times with the >>system cpu load very high (and the disk LED off). >> >>IMHO the CPU scheduling is OK but the IO scheduling acts up here. >> >>The test system is a 2.4GHz P4 with 512M RAM and a 55MB/s udma IDE harddisk. >> >>The tests load the system to loadavg > 30. IO should be about 20MB/s on avg. >> >>Enclosed are vmstat -1 logs for 2.6-test9-Vanilla, followed by 2.6-test8-Vanilla >>(-mm1 behaves similar), 2.4.22-Vanilla and 2.4.21+swsusp all compiled wo preempt. >> >>IO on 2.6 stops now for seconds at a time. -test8 is worse than -test9 >> > >We see the same delta at OSDL. Try repeating your tests with 'elevator=deadline' >to confirm. >For example, on the 8-cpu platform: >STP id Kernel Name MaxJPM Change Options >281669 linux-2.6.0-test8 7014.42 0.0 >281671 linux-2.6.0-test8 8294.94 +18.26% elevator=deadline > >The -mm kernels don't show this big delta. We also do not see this delta on >smaller machines > I'm working with Randy to fix this. Attached is what I have so far. See how you go with it.