cpufreq: intel_pstate: Account for IO wait time
authorPhilippe Longepe <philippe.longepe@intel.com>
Fri, 4 Dec 2015 16:40:35 +0000 (17:40 +0100)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Thu, 10 Dec 2015 00:17:40 +0000 (01:17 +0100)
commit63d1d656a5232f2f189b217b50542eadcf9d74ae
tree92372ee9b437e67a6a49c1749dde06b1fb5b3564
parente70eed2b64545ab5c9d2f4d43372d79762f1b985
cpufreq: intel_pstate: Account for IO wait time

In cases where we have many IOs, the global load becomes low and the
load algorithm will decrease the requested P-State. Because of that,
the IOs overheads will increase and impact the IO performances.

To improve IO bound work, we can count the io-wait time as busy time
in calculating CPU busy.

This change uses get_cpu_iowait_time_us() to obtain the IO wait time value
and converts time into number of cycles spent waiting on IO at the TSC
rate. At the moment, this trick is only used for Atom.

Signed-off-by: Philippe Longepe <philippe.longepe@intel.com>
Signed-off-by: Stephane Gasparini <stephane.gasparini@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/cpufreq/intel_pstate.c