On Thu, Jun 02, 2016 at 07:57:19PM +0800, Wanpeng Li wrote: > From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> > > I observed that sometimes st is 100% instantaneous, then idle is 100% > even if there is a cpu hog on the guest cpu after the cpu hotplug comes > back(N.B. both guest and host are latest 4.7-rc1, this can not always > be readily reproduced). I add trace to capture it as below: > > cpuhp/1-12 [001] d.h1 167.461657: account_process_tick: steal = 1291385514, prev_steal_time = 0 > cpuhp/1-12 [001] d.h1 167.461659: account_process_tick: steal_jiffies = 1291 > <idle>-0 [001] d.h1 167.462663: account_process_tick: steal = 18732255, prev_steal_time = 1291000000 > <idle>-0 [001] d.h1 167.462664: account_process_tick: steal_jiffies = 18446744072437 > > The steal clock warps and then steal_jiffies overflow, this patch align > prev_steal_time to the new steal clock timestamp, in order to avoid > overflow and st stuff can continue to work. I would rather suggest fixing the steal clock thing to not jump like that; is that at all possible? -- 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
