Messages in this thread | | | From | Andrea Righi <> | Subject | Re: [RFC][PATCH] per-task I/O throttling | Date | Fri, 11 Jan 2008 16:29:44 +0100 (MET) |
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Peter Zijlstra wrote: >> >> Anyway, I'm wondering if it's possible (and how) to already do this with >> process containers... > > I think there is an IO controller somewhere based on CFQ. > > I don't like this patch, because it throttles requests/s, and that > doesn't say much. If a task would generate a very seeky load it could > still tie up the disk even with a relatively low setting. >
Very true. A seeky intensive process wouldn't be limited at all. And I'm sure there're better ways/models to satisfy my needs.
A suggestion (off-list) has been to try with ionice that seems to be the right solution to limit the I/O activity of single processes, but it doens't allow to define policies based on UIDs or GIDs.
BTW I don't have any number to compare the effectiveness of the priority approach vs the throttling approach. Here is a very quick test made on my PC (not sure if glxgears is the right benchmark to evaluate the system responsiveness):
>>>>>> starting: glxgears <<<<<< 3564 frames in 5.0 seconds = 711.722 FPS 3953 frames in 5.0 seconds = 790.598 FPS 3969 frames in 5.0 seconds = 793.794 FPS >>>>>> starting: md5sum /usr/lib/* <<<<<< 3769 frames in 5.0 seconds = 753.189 FPS 2877 frames in 5.0 seconds = 572.843 FPS 3481 frames in 5.0 seconds = 696.071 FPS 3775 frames in 5.0 seconds = 751.404 FPS 2781 frames in 5.0 seconds = 556.118 FPS 3209 frames in 5.0 seconds = 641.064 FPS 2843 frames in 5.0 seconds = 565.697 FPS >>>>>> starting: echo 100 > /proc/`pidof md5sum`/io_throttle <<<<<< 3652 frames in 5.0 seconds = 730.253 FPS 3669 frames in 5.0 seconds = 733.734 FPS 3797 frames in 5.0 seconds = 759.234 FPS 3883 frames in 5.0 seconds = 776.488 FPS 3895 frames in 5.0 seconds = 778.868 FPS 3845 frames in 5.0 seconds = 768.968 FPS 3829 frames in 5.0 seconds = 765.793 FPS
>>>>>> flush caches (/proc/sys/vm/drop_caches) <<<<<<
>>>>>> starting: glxgears <<<<<< 3763 frames in 5.0 seconds = 752.539 FPS 3818 frames in 5.0 seconds = 763.483 FPS >>>>>> starting: ionice -c3 md5sum /usr/lib/* <<<<<< 3443 frames in 5.0 seconds = 688.597 FPS 3202 frames in 5.0 seconds = 640.390 FPS 3807 frames in 5.0 seconds = 761.391 FPS 3053 frames in 5.0 seconds = 610.539 FPS 2759 frames in 5.0 seconds = 551.790 FPS 2975 frames in 5.0 seconds = 594.873 FPS 2993 frames in 5.0 seconds = 596.709 FPS 3250 frames in 5.0 seconds = 649.857 FPS 3494 frames in 5.0 seconds = 698.688 FPS
-Andrea
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