Re: Problem: Possible regression in intel_pstate on 3.12

Joakim Hernberg
2014-01-12T01:43:17Z

Hello Dirk,

I don't seem to be able to apply this patch? For what kernel is it
meant, and is it complete?

Best wishes,

On Mon, 16 Dec 2013 09:28:19 -0800
Dirk Brandewie <dirk.brandewie@gmail.com> wrote:

> Hi Joakim,
>
> Add the following patch to your v3.12 kernel and collect some data
> with the command and send the resulting perf.data file:
> perf record -a -c 1 -e power:pstate_sample sleep 10
>
>
> TIA
> --Dirk
>
> commit b3dc2c2a106cea68e4c9c0f4747b15291113c4ae
> Author: Dirk Brandewie <dirk.j.brandewie@intel.com>
> Date: Mon Dec 2 09:56:46 2013 -0800
>
> intel_pstate: Add trace point to report internal state.
>
> Add perf trace event "power:pstate_sample" to report driver
> state to aid in diagnosing issues reported against intel_pstate.
>
> Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
> ---
> drivers/cpufreq/intel_pstate.c | 22 ++++++++++++++++++
> include/trace/events/power.h | 53
> ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 75
> insertions(+)
>
> diff --git a/drivers/cpufreq/intel_pstate.c
> b/drivers/cpufreq/intel_pstate.c index 5f1cbae..c4f14d1 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -50,6 +50,8 @@ static inline int32_t div_fp(int32_t x, int32_t y)
> return div_s64((int64_t)x << FRAC_BITS, (int64_t)y);
> }
>
> +static u64 energy_divisor;
> +
> struct sample {
> int32_t core_pct_busy;
> u64 aperf;
> @@ -512,6 +514,7 @@ static inline void intel_pstate_sample(struct
> cpudata *cpu)
>
> rdmsrl(MSR_IA32_APERF, aperf);
> rdmsrl(MSR_IA32_MPERF, mperf);
> +
> cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT;
> cpu->samples[cpu->sample_ptr].aperf = aperf;
> cpu->samples[cpu->sample_ptr].mperf = mperf;
> @@ -565,10 +568,24 @@ static inline void
> intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
> static void intel_pstate_timer_func(unsigned long __data)
> {
> struct cpudata *cpu = (struct cpudata *) __data;
> + struct sample *sample;
> + u64 energy;
>
> intel_pstate_sample(cpu);
> +
> + sample = &cpu->samples[cpu->sample_ptr];
> + rdmsrl(MSR_PKG_ENERGY_STATUS, energy);
> +
> intel_pstate_adjust_busy_pstate(cpu);
>
> + trace_pstate_sample(fp_toint(sample->core_pct_busy),
> + fp_toint(intel_pstate_get_scaled_busy(cpu)),
> + cpu->pstate.current_pstate,
> + sample->mperf,
> + sample->aperf,
> + energy/energy_divisor,
> + sample->freq);
> +
> if (cpu->pstate.current_pstate == cpu->pstate.min_pstate) {
> cpu->min_pstate_count++;
> if (!(cpu->min_pstate_count % 5)) {
> @@ -849,6 +866,7 @@ static int __init intel_pstate_init(void)
> int cpu, rc = 0;
> const struct x86_cpu_id *id;
> struct cpu_defaults *cpu_info;
> + u64 units;
>
> if (no_load)
> return -ENODEV;
> @@ -882,8 +900,12 @@ static int __init intel_pstate_init(void)
> if (rc)
> goto out;
>
> + rdmsrl(MSR_RAPL_POWER_UNIT, units);
> + energy_divisor = 1 << ((units >> 8) & 0x1f); /* bits{12:8} */
> +
> intel_pstate_debug_expose_params();
> intel_pstate_sysfs_expose_params();
> +
> return rc;
> out:
> get_online_cpus();
> diff --git a/include/trace/events/power.h
> b/include/trace/events/power.h index cda100d..9e9475c 100644
> --- a/include/trace/events/power.h
> +++ b/include/trace/events/power.h
> @@ -35,6 +35,59 @@ DEFINE_EVENT(cpu, cpu_idle,
> TP_ARGS(state, cpu_id)
> );
>
> +TRACE_EVENT(pstate_sample,
> +
> + TP_PROTO(u32 core_busy,
> + u32 scaled_busy,
> + u32 state,
> + u64 mperf,
> + u64 aperf,
> + u32 energy,
> + u32 freq
> + ),
> +
> + TP_ARGS(core_busy,
> + scaled_busy,
> + state,
> + mperf,
> + aperf,
> + energy,
> + freq
> + ),
> +
> + TP_STRUCT__entry(
> + __field(u32, core_busy)
> + __field(u32, scaled_busy)
> + __field(u32, state)
> + __field(u64, mperf)
> + __field(u64, aperf)
> + __field(u32, energy)
> + __field(u32, freq)
> +
> + ),
> +

--

Joakim