On Wed, Oct 10, 2012 at 2:58 PM, Alexander Graf <agraf@xxxxxxx> wrote: > > > On 10.10.2012, at 20:52, Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx> wrote: > >> On Wed, Oct 10, 2012 at 2:50 PM, Alexander Graf <agraf@xxxxxxx> wrote: >>> >>> >>> On 10.10.2012, at 20:39, Alexander Spyridakis >>> <a.spyridakis@xxxxxxxxxxxxxxxxxxxxxx> wrote: >>> >>> For your information, with the latest developments related to VirtIO, I run >>> netperf a couple of times to see the exact standing of network performance >>> on the guests. >>> >>> The test was to run netperf -H "ip of LAN node", which tests TCP traffic for >>> 10 seconds. >>> >>> x86 - x86: ~96 Mbps - reference between two different computers >>> ARM Host - x86: ~80 Mbps >>> ARM Guest - x86: ~ 2 Mbps - emulation >>> ARM Guest - x86: ~74 Mbps - VirtIO >>> >>> From these we conclude that: >>> >>> As expected x86 to x86 communication can reach the limit of the 100 Mbps >>> LAN. >>> The ARM board seems to not be capable of the LAN. >>> Network emulation in QEMU is more than just slow (expected). >>> >>> >>> Why is this expected? This performance drop is quite terrifying. >>> >> >> I think he means expected as in, we already know we have this >> terrifying problem. I'm looking into this right now, and I believe >> Marc is also on this. > > Ah, good :). Since you are on a dual-core machine with lots of traffic, you should get almost no vmexits for virtio queue processing. > > Since we know that this is a fast case, the big difference to emulated devices are the exits. So I'd search there :). > yes it's really staring us in our faces - we have a slow exit path. -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
