Skip to contentSkip to conversation

New: pvclock_gtod_notify invoked frequently leads to extra cpu load

Bug 190961 [email protected] 1 participant 3 messages Dec 23, 2016 – Dec 26, 2016 KVM

lore
Share & tools
lore

[email protected]

author
#0 lore raw

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: [email protected]
Reporter: [email protected]
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/

Signature · 2 lines
You are receiving this mail because:
You are watching the assignee of the bug.
author
#2 lore raw

[Bug 190961] pvclock_gtod_notify invoked frequently leads to extra cpu load

In reply to [email protected]

https://bugzilla.kernel.org/show_bug.cgi?id=190961

Chen Yu <[email protected]> changed:

What |Removed |Added
----------------------------------------------------------------------------

             Status|NEW                         |RESOLVED
         Resolution|---                         |PATCH_ALREADY_AVAILABLE
Signature · 2 lines
You are receiving this mail because:
You are watching the assignee of the bug.