Commit 23c296fb authored by Jinzhou Su's avatar Jinzhou Su Committed by Rafael J. Wysocki
Browse files

cpufreq: amd-pstate: Add more tracepoint for AMD P-State module 



Add frequency, mperf, aperf and tsc in the trace. This can be used
to debug and tune the performance of AMD P-state driver.

Use the time difference between amd_pstate_update to calculate CPU
frequency. There could be sleep in arch_freq_get_on_cpu, so do not
use it here.

Signed-off-by: default avatarJinzhou Su <Jinzhou.Su@amd.com>
Co-developed-by: default avatarHuang Rui <ray.huang@amd.com>
Signed-off-by: default avatarHuang Rui <ray.huang@amd.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent a1b6f487

drivers/cpufreq/amd-pstate-trace.h

+21 −1
Original line number Diff line number Diff line
@@ -27,6 +27,10 @@ TRACE_EVENT(amd_pstate_perf, 
	TP_PROTO(unsigned long min_perf,

		 unsigned long target_perf,

		 unsigned long capacity,

		 u64 freq,

		 u64 mperf,

		 u64 aperf,

		 u64 tsc,

		 unsigned int cpu_id,

		 bool changed,

		 bool fast_switch
@@ -35,6 +39,10 @@ TRACE_EVENT(amd_pstate_perf, 
	TP_ARGS(min_perf,

		target_perf,

		capacity,

		freq,

		mperf,

		aperf,

		tsc,

		cpu_id,

		changed,

		fast_switch
@@ -44,6 +52,10 @@ TRACE_EVENT(amd_pstate_perf, 
		__field(unsigned long, min_perf)

		__field(unsigned long, target_perf)

		__field(unsigned long, capacity)

		__field(unsigned long long, freq)

		__field(unsigned long long, mperf)

		__field(unsigned long long, aperf)

		__field(unsigned long long, tsc)

		__field(unsigned int, cpu_id)

		__field(bool, changed)

		__field(bool, fast_switch)
@@ -53,15 +65,23 @@ TRACE_EVENT(amd_pstate_perf, 
		__entry->min_perf = min_perf;

		__entry->target_perf = target_perf;

		__entry->capacity = capacity;

		__entry->freq = freq;

		__entry->mperf = mperf;

		__entry->aperf = aperf;

		__entry->tsc = tsc;

		__entry->cpu_id = cpu_id;

		__entry->changed = changed;

		__entry->fast_switch = fast_switch;

		),



	TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu cpu_id=%u changed=%s fast_switch=%s",

	TP_printk("amd_min_perf=%lu amd_des_perf=%lu amd_max_perf=%lu freq=%llu mperf=%llu aperf=%llu tsc=%llu cpu_id=%u changed=%s fast_switch=%s",

		  (unsigned long)__entry->min_perf,

		  (unsigned long)__entry->target_perf,

		  (unsigned long)__entry->capacity,

		  (unsigned long long)__entry->freq,

		  (unsigned long long)__entry->mperf,

		  (unsigned long long)__entry->aperf,

		  (unsigned long long)__entry->tsc,

		  (unsigned int)__entry->cpu_id,

		  (__entry->changed) ? "true" : "false",

		  (__entry->fast_switch) ? "true" : "false"

drivers/cpufreq/amd-pstate.c

+57 −2
Original line number Diff line number Diff line
@@ -65,6 +65,18 @@ MODULE_PARM_DESC(shared_mem, 


static struct cpufreq_driver amd_pstate_driver;



/**

 * struct  amd_aperf_mperf

 * @aperf: actual performance frequency clock count

 * @mperf: maximum performance frequency clock count

 * @tsc:   time stamp counter

 */

struct amd_aperf_mperf {

	u64 aperf;

	u64 mperf;

	u64 tsc;

};



/**

 * struct amd_cpudata - private CPU data for AMD P-State

 * @cpu: CPU number
@@ -81,6 +93,9 @@ static struct cpufreq_driver amd_pstate_driver; 
 * @min_freq: the frequency that mapped to lowest_perf

 * @nominal_freq: the frequency that mapped to nominal_perf

 * @lowest_nonlinear_freq: the frequency that mapped to lowest_nonlinear_perf

 * @cur: Difference of Aperf/Mperf/tsc count between last and current sample

 * @prev: Last Aperf/Mperf/tsc count value read from register

 * @freq: current cpu frequency value

 * @boost_supported: check whether the Processor or SBIOS supports boost mode

 *

 * The amd_cpudata is key private data for each CPU thread in AMD P-State, and
@@ -102,6 +117,10 @@ struct amd_cpudata { 
	u32	nominal_freq;

	u32	lowest_nonlinear_freq;



	struct amd_aperf_mperf cur;

	struct amd_aperf_mperf prev;



	u64 freq;

	bool	boost_supported;

};
@@ -211,6 +230,39 @@ static inline void amd_pstate_update_perf(struct amd_cpudata *cpudata, 
					    max_perf, fast_switch);

}



static inline bool amd_pstate_sample(struct amd_cpudata *cpudata)

{

	u64 aperf, mperf, tsc;

	unsigned long flags;



	local_irq_save(flags);

	rdmsrl(MSR_IA32_APERF, aperf);

	rdmsrl(MSR_IA32_MPERF, mperf);

	tsc = rdtsc();



	if (cpudata->prev.mperf == mperf || cpudata->prev.tsc == tsc) {

		local_irq_restore(flags);

		return false;

	}



	local_irq_restore(flags);



	cpudata->cur.aperf = aperf;

	cpudata->cur.mperf = mperf;

	cpudata->cur.tsc =  tsc;

	cpudata->cur.aperf -= cpudata->prev.aperf;

	cpudata->cur.mperf -= cpudata->prev.mperf;

	cpudata->cur.tsc -= cpudata->prev.tsc;



	cpudata->prev.aperf = aperf;

	cpudata->prev.mperf = mperf;

	cpudata->prev.tsc = tsc;



	cpudata->freq = div64_u64((cpudata->cur.aperf * cpu_khz), cpudata->cur.mperf);



	return true;

}



static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,

			      u32 des_perf, u32 max_perf, bool fast_switch)

{
@@ -226,8 +278,11 @@ static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf, 
	value &= ~AMD_CPPC_MAX_PERF(~0L);

	value |= AMD_CPPC_MAX_PERF(max_perf);



	trace_amd_pstate_perf(min_perf, des_perf, max_perf,

	if (trace_amd_pstate_perf_enabled() && amd_pstate_sample(cpudata)) {

		trace_amd_pstate_perf(min_perf, des_perf, max_perf, cpudata->freq,

			cpudata->cur.mperf, cpudata->cur.aperf, cpudata->cur.tsc,

				cpudata->cpu, (value != prev), fast_switch);

	}



	if (value == prev)

		return;