Hi Yu Chen, Thanks for your response! On Tue, Dec 11, 2018 at 11:12:21AM +0800, Yu Chen wrote: > Hi Joey, > On Mon, Dec 10, 2018 at 02:31:53PM +0800, joeyli wrote: > > Hi Chen Yu and ACPI experts, > > > > On Sat, May 05, 2018 at 07:53:22PM +0800, Chen Yu wrote: > > > According to current implementation of acpi_pad driver, > > > it does not make sense to spawn any power saving threads > > > on the cpus which are already idle - it might bring > > > unnecessary overhead on these idle cpus and causes power > > > waste. So verify the condition that if the number of 'busy' > > > cpus exceeds the amount of the 'forced idle' cpus is met. > > > This is applicable due to round-robin attribute of the > > > power saving threads, otherwise ignore the setting/ACPI > > > notification. > > > > > > Suggested-by: Lenny Szubowicz <lszubowi@xxxxxxxxxx> > > > Suggested-by: Len Brown <lenb@xxxxxxxxxx> > > > Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> > > > Cc: Lenny Szubowicz <lszubowi@xxxxxxxxxx> > > > Cc: Len Brown <lenb@xxxxxxxxxx> > > > Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > > > Cc: Rui Zhang <rui.zhang@xxxxxxxxx> > > > Cc: linux-acpi@xxxxxxxxxxxxxxx > > > Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx> > > > > Do you have any news for this patch? Why it did not merged by kernel > > maineline? > > > We are evaluating if this could be integrated into idle injection framework. > May I know if there's any requirement/background from SUSE on this? > I am also looking at your patch and idle injection framework. Currently I do not have good suggestion for your patches yet. But I will try to ready my knowledge when you send out new version. Thanks a lot! Joey Lee > > > > > --- > > > drivers/acpi/acpi_pad.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++- > > > 1 file changed, 51 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c > > > index 552c1f7..515e60e 100644 > > > --- a/drivers/acpi/acpi_pad.c > > > +++ b/drivers/acpi/acpi_pad.c > > > @@ -254,12 +254,62 @@ static void set_power_saving_task_num(unsigned int num) > > > } > > > } > > > > > > +/* > > > + * Extra acpi_pad threads should not be created until > > > + * the requested idle count is less than/equals to the > > > + * number of the busy cpus - it does not make sense to > > > + * throttle the idle cpus. > > > + */ > > > +#define SAMPLE_INTERVAL_JIF 20 > > > + > > > +static u64 get_idle_time(int cpu) > > > +{ > > > + u64 idle, idle_usecs = -1ULL; > > > + > > > + idle_usecs = get_cpu_idle_time_us(cpu, NULL); > > > + > > > + if (idle_usecs == -1ULL) > > > + idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE]; > > > + else > > > + idle = idle_usecs * NSEC_PER_USEC; > > > + > > > + return idle; > > > +} > > > + > > > +static bool idle_nr_valid(unsigned int num_cpus) > > > +{ > > > + int busy_nr = 0, i = 0, load_thresh = 100 - idle_pct; > > > + > > > + if (!num_cpus) > > > + return true; > > > + > > > + for_each_online_cpu(i) { > > > + u64 wall_time, idle_time; > > > + unsigned int elapsed_delta, idle_delta, load; > > > + > > > + wall_time = jiffies64_to_nsecs(get_jiffies_64()); > > > + idle_time = get_idle_time(i); > > > + /* Wait and see... */ > > > + schedule_timeout_uninterruptible(SAMPLE_INTERVAL_JIF); > > > + > > > + idle_delta = get_idle_time(i) - idle_time; > > > + elapsed_delta = jiffies64_to_nsecs(get_jiffies_64()) - wall_time; > > > + idle_delta = (idle_delta > elapsed_delta) ? elapsed_delta : idle_delta; > > > + load = 100 * (elapsed_delta - idle_delta) / elapsed_delta; > > > + if (load >= load_thresh) > > > + busy_nr++; > > > + } > > > + > > > + return (busy_nr >= num_cpus) ? true : false; > > > +} > > > + > > > static void acpi_pad_idle_cpus(unsigned int num_cpus) > > > { > > > get_online_cpus(); > > > > > > num_cpus = min_t(unsigned int, num_cpus, num_online_cpus()); > > > - set_power_saving_task_num(num_cpus); > > > + if (idle_nr_valid(num_cpus)) > > > + set_power_saving_task_num(num_cpus); > > > > > > put_online_cpus(); > > > } > > > -- > > > 2.7.4 > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > > More majordomo info at http://vger.kernel.org/majordomo-info.html