On Wednesday, March 30, 2016 05:29:18 PM Jörg Otte wrote:
> 2016-03-30 13:05 GMT+02:00 Rafael J. Wysocki <raf...@kernel.org>:
> > On Wed, Mar 30, 2016 at 12:17 PM, Jörg Otte <jrg.o...@gmail.com> wrote:
> >> 2016-03-29 23:34 GMT+02:00 Rafael J. Wysocki <r...@rjwysocki.net>:
> >>> On Tuesday, March 29, 2016 07:32:27 PM Jörg Otte wrote:
> >>>> 2016-03-29 19:24 GMT+02:00 Jörg Otte <jrg.o...@gmail.com>:
> >>>> > in v4.5 and earlier intel-pstate downscaled idle processors (load
> >>>> > 0.1-0.2%) to minumum frequency, in my case 800MHz.
> >>>> >
> >>>> > Now in v4.6-rc1 the characteristic has dramatically changed. If in
> >>>> > idle the processor frequency is more or less a few MHz around 2500Mhz.
> >>>> > This is the maximum non turbo frequency.
> >>>> >
> >>>> > No difference between powersafe or performance governor.
> >>>> >
> >>>> > I currently use acpi_cpufreq which works as usual.
> >>>> >
> >>>> > Processor:
> >>>> > Intel(R) Core(TM) i5-4200M CPU @ 2.50GHz (family: 0x6, model: 0x3c,
> >>>> > stepping: 0x3)
> >>>> >
> >>>> > Last known good kernel is: 4.5.0-01127-g9256d5a
> >>>> > First known bad kernel is: 4.5.0-02535-g09fd671
> >>>> >
> >>>> > There is
> >>>> > commit 277edba Merge tag 'pm+acpi-4.6-rc1-1' of
> >>>> > git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
> >>>> > in between, which brought a few changes in intel_pstate.
> >>>
> >>> Can you please check commit a4675fbc4a7a (cpufreq: intel_pstate: Replace
> >>> timers
> >>> with utilization update callbacks)?
> >>>
> >> Yes , this solved the problem for me.
> >> I had to resolve some conflicts myself when reverting that
> >> commit. Hard work :).
> >
> > Thanks for doing this. Can you please post the revert patch you have used?
> >
>
> The patch is on top of 4.5.0-02535-g09fd671.
> I'm not sure what gmail is doing with spaces and tabs,
> so I attach the revert patch.
That worked, thanks!
> >> Here is a 10-seconds trace of the used frequencies when
> >> in "desktop-idle":
> >>
> >> driver cpu0 cpu1 cpu2 cpu3
> >> -------------------------------------
> >> intel_pstate ( 800 928 941 1200) MHz load:( 0.2)%
> >> intel_pstate ( 800 928 1181 1800) MHz load:( 0.0)%
> >> intel_pstate ( 1675 1576 1347 800) MHz load:( 0.0)%
> >> intel_pstate ( 1198 1576 842 800) MHz load:( 0.5)%
> >> intel_pstate ( 800 1181 1113 1600) MHz load:( 0.0)%
> >> intel_pstate ( 808 1181 805 800) MHz load:( 0.5)%
> >> intel_pstate ( 844 1191 900 1082) MHz load:( 0.3)%
> >> intel_pstate ( 816 1191 800 800) MHz load:( 0.0)%
> >> intel_pstate ( 800 905 892 1082) MHz load:( 0.2)%
> >> intel_pstate ( 945 905 1340 800) MHz load:( 0.3)%
> >
> > Please also run turbostat with and without your revert patch applied.
> >
>
> turbostat without revert
> Kernel: 4.5.0-02535-g09fd671
> -----------------------------
> CPUID(7): No-SGX
> CPU Avg_MHz Busy% Bzy_MHz TSC_MHz
> - 13 0.53 2514 2495
> 0 14 0.55 2518 2495
> 1 8 0.33 2527 2495
> 2 15 0.60 2506 2495
> 3 16 0.62 2509 2495
>
> turbostat after revert of commit a4675fbc4a7a
> kernel: 4.5.0-reva4675fbc4a7a-02536-g77225b1
> ------------------------------
> CPUID(7): No-SGX
> CPU Avg_MHz Busy% Bzy_MHz TSC_MHz
> - 4 0.35 1142 2494
> 0 1 0.11 1016 2494
> 1 2 0.17 961 2494
> 2 10 0.82 1215 2494
> 3 3 0.29 1086 2494
> CPU Avg_MHz Busy% Bzy_MHz TSC_MHz
> - 4 0.46 885 2494
> 0 1 0.12 889 2494
> 1 1 0.16 885 2494
> 2 10 1.15 883 2494
> 3 4 0.40 891 2494
Clearly, there's something fishy here.
I've simplified your revert patch somewhat. Can you please test if the one
below still helps?
---
drivers/cpufreq/intel_pstate.c | 59 ++++++++++++++++++++++-------------------
1 file changed, 32 insertions(+), 27 deletions(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -71,7 +71,7 @@ struct sample {
u64 mperf;
u64 tsc;
int freq;
- u64 time;
+ ktime_t time;
};
struct pstate_data {
@@ -103,13 +103,13 @@ struct _pid {
struct cpudata {
int cpu;
- struct update_util_data update_util;
+ struct timer_list timer;
struct pstate_data pstate;
struct vid_data vid;
struct _pid pid;
- u64 last_sample_time;
+ ktime_t last_sample_time;
u64 prev_aperf;
u64 prev_mperf;
u64 prev_tsc;
@@ -882,7 +882,7 @@ static inline void intel_pstate_calc_bus
sample->core_pct_busy = (int32_t)core_pct;
}
-static inline bool intel_pstate_sample(struct cpudata *cpu, u64 time)
+static inline bool intel_pstate_sample(struct cpudata *cpu)
{
u64 aperf, mperf;
unsigned long flags;
@@ -899,7 +899,7 @@ static inline bool intel_pstate_sample(s
local_irq_restore(flags);
cpu->last_sample_time = cpu->sample.time;
- cpu->sample.time = time;
+ cpu->sample.time = ktime_get();
cpu->sample.aperf = aperf;
cpu->sample.mperf = mperf;
cpu->sample.tsc = tsc;
@@ -957,7 +957,7 @@ static inline int32_t get_target_pstate_
static inline int32_t get_target_pstate_use_performance(struct cpudata *cpu)
{
int32_t core_busy, max_pstate, current_pstate, sample_ratio;
- u64 duration_ns;
+ s64 duration_ns;
intel_pstate_calc_busy(cpu);
@@ -978,14 +978,15 @@ static inline int32_t get_target_pstate_
core_busy = mul_fp(core_busy, div_fp(max_pstate, current_pstate));
/*
- * Since our utilization update callback will not run unless we are
- * in C0, check if the actual elapsed time is significantly greater (3x)
- * than our sample interval. If it is, then we were idle for a long
- * enough period of time to adjust our busyness.
+ * Since we have a deferred timer, it will not fire unless
+ * we are in C0. So, determine if the actual elapsed time
+ * is significantly greater (3x) than our sample interval. If it
+ * is, then we were idle for a long enough period of time
+ * to adjust our busyness.
*/
- duration_ns = cpu->sample.time - cpu->last_sample_time;
- if ((s64)duration_ns > pid_params.sample_rate_ns * 3
- && cpu->last_sample_time > 0) {
+ duration_ns = ktime_to_ns(ktime_sub(cpu->sample.time,
+ cpu->last_sample_time));
+ if (duration_ns > pid_params.sample_rate_ns * 3) {
sample_ratio = div_fp(int_tofp(pid_params.sample_rate_ns),
int_tofp(duration_ns));
core_busy = mul_fp(core_busy, sample_ratio);
@@ -1032,17 +1033,19 @@ static inline void intel_pstate_adjust_b
get_avg_frequency(cpu));
}
-static void intel_pstate_update_util(struct update_util_data *data, u64 time,
- unsigned long util, unsigned long max)
+static void intel_pstate_timer_func(unsigned long __data)
{
- struct cpudata *cpu = container_of(data, struct cpudata, update_util);
- u64 delta_ns = time - cpu->sample.time;
+ struct cpudata *cpu = (struct cpudata *) __data;
+ bool sample_taken = intel_pstate_sample(cpu);
- if ((s64)delta_ns >= pid_params.sample_rate_ns) {
- bool sample_taken = intel_pstate_sample(cpu, time);
+ if (sample_taken) {
+ int delay;
- if (sample_taken && !hwp_active)
+ if (!hwp_active)
intel_pstate_adjust_busy_pstate(cpu);
+
+ delay = msecs_to_jiffies(pid_params.sample_rate_ms);
+ mod_timer_pinned(&cpu->timer, jiffies + delay);
}
}
@@ -1099,11 +1102,15 @@ static int intel_pstate_init_cpu(unsigne
intel_pstate_get_cpu_pstates(cpu);
+ init_timer_deferrable(&cpu->timer);
+ cpu->timer.data = (unsigned long)cpu;
+ cpu->timer.expires = jiffies + HZ/100;
+ cpu->timer.function = intel_pstate_timer_func;
+
intel_pstate_busy_pid_reset(cpu);
- intel_pstate_sample(cpu, 0);
+ intel_pstate_sample(cpu);
- cpu->update_util.func = intel_pstate_update_util;
- cpufreq_set_update_util_data(cpunum, &cpu->update_util);
+ add_timer_on(&cpu->timer, cpunum);
pr_debug("intel_pstate: controlling: cpu %d\n", cpunum);
@@ -1187,8 +1194,7 @@ static void intel_pstate_stop_cpu(struct
pr_debug("intel_pstate: CPU %d exiting\n", cpu_num);
- cpufreq_set_update_util_data(cpu_num, NULL);
- synchronize_sched();
+ del_timer_sync(&all_cpu_data[cpu_num]->timer);
if (hwp_active)
return;
@@ -1455,8 +1461,7 @@ out:
get_online_cpus();
for_each_online_cpu(cpu) {
if (all_cpu_data[cpu]) {
- cpufreq_set_update_util_data(cpu, NULL);
- synchronize_sched();
+ del_timer_sync(&all_cpu_data[cpu]->timer);
kfree(all_cpu_data[cpu]);
}
}
