Hi, I'm doing extensive performance tests on KVM at the moment. In various scenarios I'm able to generate a noticeable impact while no performance metric is really impacted at all. I mean general sluggishness, like typing laging behind my fingers, commands taking a few seconds to respond. Nothing drastic or unacceptable, but I'd like to understand where it's coming from. For example, starting ~30 VMs in relatively quick succession. Or sometimes, even having ~50 mostly-idle VMs. This is on a system with 256GB ram and 24 hyper-threaded cores. I'd like to pinpoint what is causing it, but looking at sar and other output, there is absolutely nothing going on. For example: overall CPU use never gets over ~40%, usually more like 20. Load is hovering around 4 (and I can get it to over 200 before anything is "really" impacted). IO Wait is consistently 0.x%, Swap use and paging rates are practically non-existent, Disk utilization is in the tens of % at worst with svctm at most hitting about 15 milliseconds. (And my VM's are on different disks than my OS anyway). Any ideas where I can look further? Thanks. -- 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
