Bart Van Assche wrote: > On Wed, Apr 15, 2009 at 9:19 PM, Pasi Kärkkäinen <pa...@iki.fi> wrote: >> noop is usually good for the initiator. cfq has a feature (or a bug?) that >> prevents achieving queue depths deeper than 1, and thus limits your >> bandwidth a lot when there are (or should be) many ios on the fly at the >> same time. > > Do you remember on which kernel version you observed the above > behavior ? This might be a bug in the CFQ scheduler. I found the > following in the 2.6.28 changelog: "cfq-iosched: fix queue depth > detection". See also > http://www.eu.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.28 or > http://lkml.org/lkml/2008/8/22/39. >
I do not think we found the root cause. That might be it. I remember talking to Aaron Carroll and him sending the attached patch to test. We thought the part about the "It should also help alleviate problems associated with suboptimal queue-depth detection." was our issue. I see the new patch that you referenced also mentioned something about it. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to open-iscsi@googlegroups.com To unsubscribe from this group, send email to open-iscsi+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/open-iscsi -~----------~----~----~----~------~----~------~--~---
[PATCH] cfq-iosched: disable idle window for seeky processes.eml
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