https://bugzilla.kernel.org/show_bug.cgi?id=190961 Bug ID: 190961 Summary: pvclock_gtod_notify invoked frequently leads to extra cpu load Product: Virtualization Version: unspecified Kernel Version: 4.9 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: kvm Assignee: virtualization_kvm@xxxxxxxxxxxxxxxxxxxx Reporter: yu.c.chen@xxxxxxxxx Regression: No This thread is created for tracking purpose Currently the notifier of pvclock_gtod_notify() get invoked frequently due to the periodic update_wall_time(). This might slow down the system a little bit as there might be redundant execution code path and unnecessary lock contention in update_pvclock_gtod(), which was found when I was doing suspend/resume speed testings. As pvclock_gtod_notify() should be invoked only when clocksource has changed, according to Commit 16e8d74d2da9 ("KVM: x86: notifier for clocksource changes") , either we can add a new notifier for clocksource switch, or we can simply bypass the following code in pvclock_gtod_notify() earlier if there is no clocksource switch. https://patchwork.kernel.org/patch/9487257/ -- You are receiving this mail because: You are watching the assignee of the bug. -- 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
