Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: [RFC, PATCH] cfq-iosched: remove redundant queuing detection code | Date | Tue, 10 Nov 2009 10:55:47 -0500 |
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Jens Axboe <jens.axboe@oracle.com> writes:
>> Why don't we simply use the value configured via the queue_depth sysfs >> file? > > First of all, that only covers SCSI. We could do that by having the tag > on/off functions set the same flag. But even for such devices, actual > tag depth is dependent upon what other devices are on the controller > (since it's often a shared map) and may not even be statically > detectable in the sense that actual depth is only really seen when the > device returns busy on a queue attempt. > > In most cases it would work fine, but the dynamic detection is more > reliable. The sysfs setting in reality is max setting.
OK, thanks for the patient explanation, Jens!
Cheers, Jeff
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