diff options
| author | Chen Yu <yu.c.chen@intel.com> | 2016-05-11 14:33:08 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-05-11 22:56:34 +0200 |
| commit | 4578ee7e1defe534582fe3afdb747b86023207f0 (patch) | |
| tree | 2857ab0921181c08f60d3030ba8e04656f063e53 /drivers/cpufreq/intel_pstate.c | |
| parent | c29af6f1a4e6f54e806fed1c40e7d338650b7791 (diff) | |
intel_pstate: Avoid unnecessary synchronize_sched() during initialization
Currently, in intel_pstate_clear_update_util_hook(), after
clearing the utilization update hook, we leverage
synchronize_sched() to deal with synchronization, which
is a little bit time-costly because synchronize_sched()
has to wait for all the CPUs to go through a grace period.
Actually, the synchronize_sched() is not necessary if the utilization
update hook has not been set for the given CPU yet, so make the driver
check if that's the case and avoid the synchronize_sched() call then.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=116371
Tested-by: Tian Ye <yex.tian@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
[ rjw : Rebase ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/intel_pstate.c')
| -rw-r--r-- | drivers/cpufreq/intel_pstate.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index cde1a4ecaa6e..36953b5f18de 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -168,6 +168,7 @@ struct _pid { * struct cpudata - Per CPU instance data storage * @cpu: CPU number for this instance data * @update_util: CPUFreq utility callback information + * @update_util_set: CPUFreq utility callback is set * @pstate: Stores P state limits for this CPU * @vid: Stores VID limits for this CPU * @pid: Stores PID parameters for this CPU @@ -187,6 +188,7 @@ struct cpudata { int cpu; struct update_util_data update_util; + bool update_util_set; struct pstate_data pstate; struct vid_data vid; @@ -1417,11 +1419,18 @@ static void intel_pstate_set_update_util_hook(unsigned int cpu_num) cpu->sample.time = 0; cpufreq_add_update_util_hook(cpu_num, &cpu->update_util, intel_pstate_update_util); + cpu->update_util_set = true; } static void intel_pstate_clear_update_util_hook(unsigned int cpu) { + struct cpudata *cpu_data = all_cpu_data[cpu]; + + if (!cpu_data->update_util_set) + return; + cpufreq_remove_update_util_hook(cpu); + cpu_data->update_util_set = false; synchronize_sched(); } |