On Tue, Mar 6, 2012 at 10:07 PM, Reeted <reeted@xxxxxxxxxxxxx> wrote: > On 03/06/12 13:59, Stefan Hajnoczi wrote: >> >> On Mon, Mar 5, 2012 at 4:44 PM, Martin Mailand<martin@xxxxxxxxxxxx> >> wrote: >>> >>> Am 05.03.2012 17:35, schrieb Stefan Hajnoczi: >>> >>>>> 1. Test on i7 Laptop with Cpu governor "ondemand". >>>>>> >>>>>> v0.14.1 >>>>>> bw=63492KB/s iops=15873 >>>>>> bw=63221KB/s iops=15805 >>>>>> >>>>>> v1.0 >>>>>> bw=36696KB/s iops=9173 >>>>>> bw=37404KB/s iops=9350 >>>>>> >>>>>> master >>>>>> bw=36396KB/s iops=9099 >>>>>> bw=34182KB/s iops=8545 >>>>>> >>>>>> Change the Cpu governor to "performance" >>>>>> master >>>>>> bw=81756KB/s iops=20393 >>>>>> bw=81453KB/s iops=20257 >>>> >>>> Interesting finding. Did you show the 0.14.1 results with >>>> "performance" governor? >>> >>> >>> >>> Hi Stefan, >>> all results are with "ondemand" except the one where I changed it to >>> "performance" >>> >>> Do you want a v0.14.1 test with the governor on "performance"? >> >> Yes, the reason why that would be interesting is because it allows us >> to put the performance gain with master+"performance" into >> perspective. We could see how much of a change we get. > > > > Me too, I would be interested in seeing 0.14.1 being tested with performance > governor so to compare it to master with performance governor, to make sure > that this is not a regression. > > BTW, I'll take the opportunity to say that 15.8 or 20.3 k IOPS are very low > figures compared to what I'd instinctively expect from a paravirtualized > block driver. > There are now PCIe SSD cards that do 240 k IOPS (e.g. "OCZ RevoDrive 3 x2 > max iops") which is 12-15 times higher, for something that has to go through > a real driver and a real PCI-express bus, and can't use zero-copy > techniques. > The IOPS we can give to a VM is currently less than half that of a single > SSD SATA drive (60 k IOPS or so, these days). > That's why I consider this topic of virtio-blk performances very important. > I hope there can be improvements in this sector... It depends on the benchmark configuration. virtio-blk is capable of doing 100,000s of iops, I've seen results. My guess is that you can do >100,000 read iops with virtio-blk on a good machine and stock qemu-kvm. 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
