On Thu, Apr 16, 2009 at 11:50:27AM +0200, 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. >
Iirc it has been with RHEL5/CentOS5 2.6.18 based kernels.. Mike Christie has been writing about this aswell.. dunno about what kernels he has seen it with. Then again CFQ was designed for "single disk workstations".. -- Pasi --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
