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From: Peter Zijlstra <>
Subject: [PATCH v2 0/7] Various tsc/clocksource fixes
Date: Mon, 30 Apr 2018 12:00:08 +0200	[thread overview]
Message-ID: <> (raw)

These patches are the result of the regression Diego reported against commit:

  aa83c45762a2 ("x86/tsc: Introduce early tsc clocksource")

His Core2 triggers mark_tsc_unstable() while we're running with tsc-early,
which then results in us failing to unregister the clocksource.

Furthermore, since mark_tsc_unstable() only looks at the regular tsc
clocksource, we don't even mark tsc_early UNSTABLE or de-rate it, resulting in
it actually staying a desirable clocksource.

Fixing that is a little more tricky; albeit far less critical after we
guarantee to unregister tsc-early.

Please consider these for /urgent. I've used both Fixes and stable tags
on a bunch of them because the above commit is already in v4.16 and
would need stable help.

These patches have been tested on both a Core2 and an IVB. On IVB I've both
changed intel_idle to always report the TSC unstable and mucked about with the
TSC msr from userspace to tickle the watchdog paths.

Changes since v1

 - fix __clocksource_change_rating() locking
 - removed work->kthread->watchdog hoops
 - fixed up comment

             reply	other threads:[~2018-04-30 10:04 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-30 10:00 Peter Zijlstra [this message]
2018-04-30 10:00 ` [PATCH v2 1/7] x86,tsc: Always unregister clocksource_tsc_early Peter Zijlstra
2018-05-02 14:12   ` [tip:timers/urgent] x86/tsc: " tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 2/7] clocksource: Allow clocksource_mark_unstable() on unregisered clocksources Peter Zijlstra
2018-05-02 13:35   ` Thomas Gleixner
2018-05-02 13:53     ` Peter Zijlstra
2018-05-02 14:13       ` [tip:timers/urgent] clocksource: Allow clocksource_mark_unstable() on unregistered clocksources tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 3/7] clocksource: Initialize cs->wd_list Peter Zijlstra
2018-05-02 13:37   ` Thomas Gleixner
2018-05-02 13:55     ` Peter Zijlstra
2018-05-02 14:13   ` [tip:timers/urgent] " tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 4/7] x86,tsc: Fix mark_tsc_unstable() Peter Zijlstra
2018-05-02 14:14   ` [tip:timers/urgent] x86/tsc: " tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 5/7] clocksource: Consistent de-rate when marking unstable Peter Zijlstra
2018-05-02 14:14   ` [tip:timers/urgent] " tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 6/7] clocksource: Rework stale comment Peter Zijlstra
2018-05-02 14:15   ` [tip:timers/urgent] " tip-bot for Peter Zijlstra
2018-04-30 10:00 ` [PATCH v2 7/7] clocksource: Remove kthread Peter Zijlstra
2018-05-02 14:42   ` [tip:timers/core] " tip-bot for Peter Zijlstra
2018-05-01  9:12 ` [PATCH v2 0/7] Various tsc/clocksource fixes Rafael J. Wysocki

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