1. 28 6月, 2016 1 次提交
    • R
      intel_pstate: Do not clear utilization update hooks on policy changes · 5ab666e0
      Rafael J. Wysocki 提交于
      intel_pstate_set_policy() is invoked by the cpufreq core during
      driver initialization, on changes of policy attributes (minimim and
      maximum frequency, for example) via sysfs and via CPU notifications
      from the platform firmware.  On some platforms the latter may occur
      relatively often.
      
      Commit bb6ab52f (intel_pstate: Do not set utilization update hook
      too early) made intel_pstate_set_policy() clear the CPU's utilization
      update hook before updating the policy attributes for it (and set the
      hook again after doind that), but that involves invoking
      synchronize_sched() and adds overhead to the CPU notifications
      mentioned above and to the sched-RCU handling in general.
      
      That extra overhead is arguably not necessary, because updating
      policy attributes when the CPU's utilization update hook is active
      should not lead to any adverse effects, so drop the clearing of
      the hook from intel_pstate_set_policy() and make it check if
      the hook has been set already when attempting to set it.
      
      Fixes: bb6ab52f (intel_pstate: Do not set utilization update hook too early)
      Reported-by: NJisheng Zhang <jszhang@marvell.com>
      Tested-by: NJisheng Zhang <jszhang@marvell.com>
      Tested-by: NDoug Smythies <dsmythies@telus.net>
      Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      5ab666e0
  2. 27 6月, 2016 2 次提交
  3. 25 6月, 2016 37 次提交