On Wed, Apr 11, 2012 at 5:52 PM, Michael Baysek <mbaysek@xxxxxxxxxxxxx> wrote: > I am purposefully not using O_DIRECT since most workloads will not be using > it, although I did notice better performance when I did use it. I did > already identify the page cache as a hinderance as well. If you do not use O_DIRECT in the benchmark then you are not exercising pure disk I/O and therefore the benchmark is not measuring virtio-blk performance. > I seem to have hit some performance ceilings inside of the kvm guests that > are much lower than that of the host they are running on. I am seeing a > lot more interrupts and context switches on the parent than I am in the > guests, and I am looking for any and all ways to cut these down. If you don't care about persistence of data I suggest doing the ramdisk or tmpfs inside the guest. That way you keep all "storage" operations inside the guest and avoid going through any storage interface (virtio-blk, IDE, etc). You should be able to achieve maximum performance using this approach although it does require guest configuration. Hope this helps, Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
