From: bugzilla-daemon@bugzilla.kernel.org
To: kvm@vger.kernel.org
Subject: [Bug 190961] New: pvclock_gtod_notify invoked frequently leads to extra cpu load
Date: Fri, 23 Dec 2016 08:39:21 +0000 [thread overview]
Message-ID: <bug-190961-28872@https.bugzilla.kernel.org/> (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: virtualization_kvm@kernel-bugs.osdl.org
Reporter: yu.c.chen@intel.com
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/
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next reply other threads:[~2016-12-23 8:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-23 8:39 bugzilla-daemon [this message]
2016-12-23 8:41 ` [Bug 190961] pvclock_gtod_notify invoked frequently leads to extra cpu load bugzilla-daemon
2016-12-26 4:27 ` bugzilla-daemon
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