All of lore.kernel.org
 help / color / mirror / Atom feed
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/

-- 
You are receiving this mail because:
You are watching the assignee of the bug.

             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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=bug-190961-28872@https.bugzilla.kernel.org/ \
    --to=bugzilla-daemon@bugzilla.kernel.org \
    --cc=kvm@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.