On 06-05-16, 01:30, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > > As reported in KBZ 69821: > > "With CONFIG_HZ_PERIODIC=y cpu stays at the lowest frequcency 800MHz > even if usage goes to 100%, frequency does not scale up, the governor > in use is ondemand. Neither works conservative. Performance and > userspace governors work as expected. > > With CONFIG_NO_HZ_IDLE or CONFIG_NO_HZ_FULL cpu scales up with ondemand > as expected." > > Analysis carried out by Chen Yu leads to the conclusion that the > observed issue is due to idle_time in dbs_update() representing a > negative number in which case the function will return 0 as the load > (unless load is greater than 0 for another CPU sharing the policy), > although that need not be the right choice. > > Indeed, idle_time representing a negative number means that during > the last sampling interval the CPU was almost 100% busy on the rough > average, so 100 should be returned as the load in that case. > > Modify the code accordingly and rearrange it to clarify the handling > of all of the special cases in it. While at it, also avoid returning > zero as the load if time_elapsed is 0 (it doesn't really make sense > to return 0 then). > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=69821 > Tested-by: Chen Yu <yu.c.c...@intel.com> > Tested-by: Timo Valtoaho <timo.valto...@gmail.com> > Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > --- > drivers/cpufreq/cpufreq_governor.c | 87 > +++++++++++++++++++++---------------- > 1 file changed, 51 insertions(+), 36 deletions(-)
Acked-by: Viresh Kumar <viresh.ku...@linaro.org> -- viresh
