On 08/17/2011 09:38 PM, Sasha Levin wrote: > On Wed, 2011-08-17 at 16:00 -0700, Avi Kivity wrote: > > On 08/16/2011 12:47 PM, Sasha Levin wrote: > > > This patch adds support for an optional stats vq that works similary to the > > > stats vq provided by virtio-balloon. > > > > > > The purpose of this change is to allow collection of statistics about working > > > virtio-blk devices to easily analyze performance without having to tap into > > > the guest. > > > > > > > > > > Why can't you get the same info from the host? i.e. read sectors? > > Some of the stats you can collect from the host, but some you can't. > > The ones you can't include all the timing statistics and the internal > queue statistics (read/write merges). Surely you can time the actual amount of time the I/O takes? It doesn't account for the virtio round-trip, but does it matter? Why is the merge count important for the host? > > The idea behind providing all of the stats on the stats vq (which is > basically what you see in '/dev/block/[device]/stats') is to give a > consistent snapshot of the state of the device. > > What can you do with it? -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
