Messages in this thread | | | Date | Sat, 15 Mar 2014 06:57:23 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH] virtio-blk: make the queue depth the max supportable by the hypervisor |
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On Fri, Mar 14, 2014 at 11:34:31PM -0400, Theodore Ts'o wrote: > The current virtio block sets a queue depth of 64, which is > insufficient for very fast devices. It has been demonstrated that > with a high IOPS device, using a queue depth of 256 can double the > IOPS which can be sustained. > > As suggested by Venkatash Srinivas, set the queue depth by default to > be one half the the device's virtqueue, which is the maximum queue > depth that can be supported by the channel to the host OS (each I/O > request requires at least two VQ entries).
I don't think this should be a module parameter. The default sizing should be based of the parameters of the actual virtqueue, and if we want to allow tuning it it should be by a sysfs attribute, preferable using the same semantics as SCSI.
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