On 10/17/2016 03:40 PM, Radim Krčmář wrote: > 2016-10-14 17:02+1100, Suraj Jitindar Singh: >> Various kvm vm and vcpu stats are provided via debugfs entries. >> Currently there is no way to reset these stats back to zero for the system >> except by stopping all vms. > > It is not really resetting, just a special case of current behavior -- > top-level stats are a sum of all existing VMs/VCPUs, so we would see 0 > if they all had 0. > >> Add the ability to clear (reset back to zero) these stats on a per stat >> basis by writing to the debugfs files. > > I can see this being used before a test, but the userspace could also > read the value instead of writing and subtract it from the value after > the test to get a similar result. > > The userspace-only solution is insufficient? > > When and what do you zero? > >> The stats are just reset to zero >> irrespective of what is actually written to the file. > > Sounds good. Setting the val would be as simple, but there shouldn't be > a reason to and it is a debug interface, so we can change it anytime. > >> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx> >> --- > > I have applied it to kvm/queue for the moment, thanks. FWIW, I was thinking about another change: provide the accumulated values of the counters of all VMs that have been destroyed (basically on vm_destroy read the values and add them on top of the "forever" counters. Did not find the time to do something like this. -- 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
