Messages in this thread | | | From | Nathan Zimmer <> | Subject | [PATCH v6 0/2] cpufreq: cpufreq_driver_lock is hot on large systems | Date | Mon, 1 Apr 2013 15:11:07 -0500 |
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I am noticing the cpufreq_driver_lock is quite hot. On an idle 512 system perf shows me most of the system time is spent on this lock. This is quite significant as top shows 5% of time in system time. My solution was to first split the lock into two parts, cpu_driver_lock and cpu_data_lock, with the cpufreq_driver also being protected by the RCU. There was measurable heat left on the cpufreq_data_lock in __cpufreq_cpu_get. So in the second part I converted the cpufreq_data_lock to be a rw lock since an rcu solution was not apparent, at least to me.
v5: Go a different way and split up the lock and use the rcu v6: use bools instead of checking function pointers covert the cpufreq_data_lock to a rwlock
Nathan Zimmer (2): cpufreq: split the cpufreq_driver_lock and use the rcu cpufreq: covert the cpufreq_data_lock to a spinlock
drivers/cpufreq/cpufreq.c | 302 +++++++++++++++++++++++++++++++++------------- 1 file changed, 219 insertions(+), 83 deletions(-)
-- 1.8.1.2
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