* [PATCH 1/4] cpufreq: intel_pstate: Improve accuracy by not truncating until final result
2013-10-21 16:20 [PATCH 0/4] intel_pstate updates dirk.brandewie
@ 2013-10-21 16:20 ` dirk.brandewie
2013-10-21 20:53 ` Brennan Shacklett
2013-10-21 16:20 ` [PATCH 2/4] cpufreq/intel_pstate: Correct calculation of min pstate value dirk.brandewie
` (3 subsequent siblings)
4 siblings, 1 reply; 9+ messages in thread
From: dirk.brandewie @ 2013-10-21 16:20 UTC (permalink / raw)
To: linux-pm, rjw; +Cc: Brennan Shacklett, Brennan Shacklet
From: Brennan Shacklett <brennan@genyes.org>
This patch addresses Bug 60727
(https://bugzilla.kernel.org/show_bug.cgi?id=60727)
which was due to the truncation of intermediate values in the
calculations, which causes the code to consistently underestimate the
current cpu frequency, specifically 100% cpu utilization was truncated
down to the setpoint of 97%. This patch fixes the problem by keeping
the results of all intermediate calculations as fixed point numbers
rather scaling them back and forth between integers and fixed point.
Signed-off-by: Brennan Shacklet <bpshacklett@gmail.com>
Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
---
drivers/cpufreq/intel_pstate.c | 33 +++++++++++++++------------------
1 file changed, 15 insertions(+), 18 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index d576489..9f42b0a 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -48,7 +48,7 @@ static inline int32_t div_fp(int32_t x, int32_t y)
}
struct sample {
- int core_pct_busy;
+ int32_t core_pct_busy;
u64 aperf;
u64 mperf;
int freq;
@@ -68,7 +68,7 @@ struct _pid {
int32_t i_gain;
int32_t d_gain;
int deadband;
- int last_err;
+ int32_t last_err;
};
struct cpudata {
@@ -153,16 +153,15 @@ static inline void pid_d_gain_set(struct _pid *pid, int percent)
pid->d_gain = div_fp(int_tofp(percent), int_tofp(100));
}
-static signed int pid_calc(struct _pid *pid, int busy)
+static signed int pid_calc(struct _pid *pid, int32_t busy)
{
- signed int err, result;
+ signed int result;
int32_t pterm, dterm, fp_error;
int32_t integral_limit;
- err = pid->setpoint - busy;
- fp_error = int_tofp(err);
+ fp_error = int_tofp(pid->setpoint) - busy;
- if (abs(err) <= pid->deadband)
+ if (abs(fp_error) <= int_tofp(pid->deadband))
return 0;
pterm = mul_fp(pid->p_gain, fp_error);
@@ -176,8 +175,8 @@ static signed int pid_calc(struct _pid *pid, int busy)
if (pid->integral < -integral_limit)
pid->integral = -integral_limit;
- dterm = mul_fp(pid->d_gain, (err - pid->last_err));
- pid->last_err = err;
+ dterm = mul_fp(pid->d_gain, fp_error - pid->last_err);
+ pid->last_err = fp_error;
result = pterm + mul_fp(pid->integral, pid->i_gain) + dterm;
@@ -436,8 +435,9 @@ static inline void intel_pstate_calc_busy(struct cpudata *cpu,
struct sample *sample)
{
u64 core_pct;
- core_pct = div64_u64(sample->aperf * 100, sample->mperf);
- sample->freq = cpu->pstate.max_pstate * core_pct * 1000;
+ core_pct = div64_u64(int_tofp(sample->aperf * 100),
+ sample->mperf);
+ sample->freq = fp_toint(cpu->pstate.max_pstate * core_pct * 1000);
sample->core_pct_busy = core_pct;
}
@@ -469,22 +469,19 @@ static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
mod_timer_pinned(&cpu->timer, jiffies + delay);
}
-static inline int intel_pstate_get_scaled_busy(struct cpudata *cpu)
+static inline int32_t intel_pstate_get_scaled_busy(struct cpudata *cpu)
{
- int32_t busy_scaled;
int32_t core_busy, max_pstate, current_pstate;
- core_busy = int_tofp(cpu->samples[cpu->sample_ptr].core_pct_busy);
+ core_busy = cpu->samples[cpu->sample_ptr].core_pct_busy;
max_pstate = int_tofp(cpu->pstate.max_pstate);
current_pstate = int_tofp(cpu->pstate.current_pstate);
- busy_scaled = mul_fp(core_busy, div_fp(max_pstate, current_pstate));
-
- return fp_toint(busy_scaled);
+ return mul_fp(core_busy, div_fp(max_pstate, current_pstate));
}
static inline void intel_pstate_adjust_busy_pstate(struct cpudata *cpu)
{
- int busy_scaled;
+ int32_t busy_scaled;
struct _pid *pid;
signed int ctl = 0;
int steps;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH 3/4] cpufreq/intel_pstate: Refactor driver to support CPUs with different MSR layouts
2013-10-21 16:20 [PATCH 0/4] intel_pstate updates dirk.brandewie
2013-10-21 16:20 ` [PATCH 1/4] cpufreq: intel_pstate: Improve accuracy by not truncating until final result dirk.brandewie
2013-10-21 16:20 ` [PATCH 2/4] cpufreq/intel_pstate: Correct calculation of min pstate value dirk.brandewie
@ 2013-10-21 16:20 ` dirk.brandewie
2013-10-21 16:20 ` [PATCH 4/4] cpufreq/intel_pstate: Add Baytrail support dirk.brandewie
2013-10-21 16:29 ` [PATCH 0/4] intel_pstate updates Dirk Brandewie
4 siblings, 0 replies; 9+ messages in thread
From: dirk.brandewie @ 2013-10-21 16:20 UTC (permalink / raw)
To: linux-pm, rjw; +Cc: Dirk Brandewie
From: Dirk Brandewie <dirk.j.brandewie@intel.com>
Non-core processors have a different MSR layout to commumicate P state
information. Refactor the driver to use CPU dependent accessors to
P state information.
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
---
drivers/cpufreq/intel_pstate.c | 144 ++++++++++++++++++++++++++++-------------
1 file changed, 98 insertions(+), 46 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 67a87e0..c41fff9 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -78,7 +78,6 @@ struct cpudata {
struct timer_list timer;
- struct pstate_adjust_policy *pstate_policy;
struct pstate_data pstate;
struct _pid pid;
@@ -100,15 +99,21 @@ struct pstate_adjust_policy {
int i_gain_pct;
};
-static struct pstate_adjust_policy default_policy = {
- .sample_rate_ms = 10,
- .deadband = 0,
- .setpoint = 97,
- .p_gain_pct = 20,
- .d_gain_pct = 0,
- .i_gain_pct = 0,
+struct pstate_funcs {
+ int (*get_max)(void);
+ int (*get_min)(void);
+ int (*get_turbo)(void);
+ void (*set)(int pstate);
};
+struct cpu_defaults {
+ struct pstate_adjust_policy pid_policy;
+ struct pstate_funcs funcs;
+};
+
+static struct pstate_adjust_policy pid_params;
+static struct pstate_funcs pstate_funcs;
+
struct perf_limits {
int no_turbo;
int max_perf_pct;
@@ -185,14 +190,14 @@ static signed int pid_calc(struct _pid *pid, int32_t busy)
static inline void intel_pstate_busy_pid_reset(struct cpudata *cpu)
{
- pid_p_gain_set(&cpu->pid, cpu->pstate_policy->p_gain_pct);
- pid_d_gain_set(&cpu->pid, cpu->pstate_policy->d_gain_pct);
- pid_i_gain_set(&cpu->pid, cpu->pstate_policy->i_gain_pct);
+ pid_p_gain_set(&cpu->pid, pid_params.p_gain_pct);
+ pid_d_gain_set(&cpu->pid, pid_params.d_gain_pct);
+ pid_i_gain_set(&cpu->pid, pid_params.i_gain_pct);
pid_reset(&cpu->pid,
- cpu->pstate_policy->setpoint,
+ pid_params.setpoint,
100,
- cpu->pstate_policy->deadband,
+ pid_params.deadband,
0);
}
@@ -226,12 +231,12 @@ struct pid_param {
};
static struct pid_param pid_files[] = {
- {"sample_rate_ms", &default_policy.sample_rate_ms},
- {"d_gain_pct", &default_policy.d_gain_pct},
- {"i_gain_pct", &default_policy.i_gain_pct},
- {"deadband", &default_policy.deadband},
- {"setpoint", &default_policy.setpoint},
- {"p_gain_pct", &default_policy.p_gain_pct},
+ {"sample_rate_ms", &pid_params.sample_rate_ms},
+ {"d_gain_pct", &pid_params.d_gain_pct},
+ {"i_gain_pct", &pid_params.i_gain_pct},
+ {"deadband", &pid_params.deadband},
+ {"setpoint", &pid_params.setpoint},
+ {"p_gain_pct", &pid_params.p_gain_pct},
{NULL, NULL}
};
@@ -336,33 +341,60 @@ static void intel_pstate_sysfs_expose_params(void)
}
/************************** sysfs end ************************/
-
-static int intel_pstate_min_pstate(void)
+static int core_get_min_pstate(void)
{
u64 value;
rdmsrl(MSR_PLATFORM_INFO, value);
return (value >> 40) & 0xFF;
}
-static int intel_pstate_max_pstate(void)
+static int core_get_max_pstate(void)
{
u64 value;
rdmsrl(MSR_PLATFORM_INFO, value);
return (value >> 8) & 0xFF;
}
-static int intel_pstate_turbo_pstate(void)
+static int core_get_turbo_pstate(void)
{
u64 value;
int nont, ret;
rdmsrl(MSR_NHM_TURBO_RATIO_LIMIT, value);
- nont = intel_pstate_max_pstate();
+ nont = core_get_max_pstate();
ret = ((value) & 255);
if (ret <= nont)
ret = nont;
return ret;
}
+static void core_set_pstate(int pstate)
+{
+ u64 val;
+
+ val = pstate << 8;
+ if (limits.no_turbo)
+ val |= (u64)1 << 32;
+
+ wrmsrl(MSR_IA32_PERF_CTL, val);
+}
+
+static struct cpu_defaults core_params = {
+ .pid_policy = {
+ .sample_rate_ms = 10,
+ .deadband = 0,
+ .setpoint = 97,
+ .p_gain_pct = 20,
+ .d_gain_pct = 0,
+ .i_gain_pct = 0,
+ },
+ .funcs = {
+ .get_max = core_get_max_pstate,
+ .get_min = core_get_min_pstate,
+ .get_turbo = core_get_turbo_pstate,
+ .set = core_set_pstate,
+ },
+};
+
static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
{
int max_perf = cpu->pstate.turbo_pstate;
@@ -383,7 +415,6 @@ static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
{
int max_perf, min_perf;
- u64 val;
intel_pstate_get_min_max(cpu, &min_perf, &max_perf);
@@ -395,11 +426,8 @@ static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
trace_cpu_frequency(pstate * 100000, cpu->cpu);
cpu->pstate.current_pstate = pstate;
- val = pstate << 8;
- if (limits.no_turbo)
- val |= (u64)1 << 32;
- wrmsrl(MSR_IA32_PERF_CTL, val);
+ pstate_funcs.set(pstate);
}
static inline void intel_pstate_pstate_increase(struct cpudata *cpu, int steps)
@@ -421,9 +449,9 @@ static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
{
sprintf(cpu->name, "Intel 2nd generation core");
- cpu->pstate.min_pstate = intel_pstate_min_pstate();
- cpu->pstate.max_pstate = intel_pstate_max_pstate();
- cpu->pstate.turbo_pstate = intel_pstate_turbo_pstate();
+ cpu->pstate.min_pstate = pstate_funcs.get_min();
+ cpu->pstate.max_pstate = pstate_funcs.get_max();
+ cpu->pstate.turbo_pstate = pstate_funcs.get_turbo();
/*
* goto max pstate so we don't slow up boot if we are built-in if we are
@@ -465,7 +493,7 @@ static inline void intel_pstate_set_sample_time(struct cpudata *cpu)
{
int sample_time, delay;
- sample_time = cpu->pstate_policy->sample_rate_ms;
+ sample_time = pid_params.sample_rate_ms;
delay = msecs_to_jiffies(sample_time);
mod_timer_pinned(&cpu->timer, jiffies + delay);
}
@@ -521,14 +549,14 @@ static void intel_pstate_timer_func(unsigned long __data)
{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long)&policy }
static const struct x86_cpu_id intel_pstate_cpu_ids[] = {
- ICPU(0x2a, default_policy),
- ICPU(0x2d, default_policy),
- ICPU(0x3a, default_policy),
- ICPU(0x3c, default_policy),
- ICPU(0x3e, default_policy),
- ICPU(0x3f, default_policy),
- ICPU(0x45, default_policy),
- ICPU(0x46, default_policy),
+ ICPU(0x2a, core_params),
+ ICPU(0x2d, core_params),
+ ICPU(0x3a, core_params),
+ ICPU(0x3c, core_params),
+ ICPU(0x3e, core_params),
+ ICPU(0x3f, core_params),
+ ICPU(0x45, core_params),
+ ICPU(0x46, core_params),
{}
};
MODULE_DEVICE_TABLE(x86cpu, intel_pstate_cpu_ids);
@@ -552,8 +580,7 @@ static int intel_pstate_init_cpu(unsigned int cpunum)
intel_pstate_get_cpu_pstates(cpu);
cpu->cpu = cpunum;
- cpu->pstate_policy =
- (struct pstate_adjust_policy *)id->driver_data;
+
init_timer_deferrable(&cpu->timer);
cpu->timer.function = intel_pstate_timer_func;
cpu->timer.data =
@@ -681,9 +708,9 @@ static int intel_pstate_msrs_not_valid(void)
rdmsrl(MSR_IA32_APERF, aperf);
rdmsrl(MSR_IA32_MPERF, mperf);
- if (!intel_pstate_min_pstate() ||
- !intel_pstate_max_pstate() ||
- !intel_pstate_turbo_pstate())
+ if (!pstate_funcs.get_max() ||
+ !pstate_funcs.get_min() ||
+ !pstate_funcs.get_turbo())
return -ENODEV;
rdmsrl(MSR_IA32_APERF, tmp);
@@ -696,10 +723,30 @@ static int intel_pstate_msrs_not_valid(void)
return 0;
}
+
+void copy_pid_params(struct pstate_adjust_policy *policy)
+{
+ pid_params.sample_rate_ms = policy->sample_rate_ms;
+ pid_params.p_gain_pct = policy->p_gain_pct;
+ pid_params.i_gain_pct = policy->i_gain_pct;
+ pid_params.d_gain_pct = policy->d_gain_pct;
+ pid_params.deadband = policy->deadband;
+ pid_params.setpoint = policy->setpoint;
+}
+
+void copy_cpu_funcs(struct pstate_funcs *funcs)
+{
+ pstate_funcs.get_max = funcs->get_max;
+ pstate_funcs.get_min = funcs->get_min;
+ pstate_funcs.get_turbo = funcs->get_turbo;
+ pstate_funcs.set = funcs->set;
+}
+
static int __init intel_pstate_init(void)
{
int cpu, rc = 0;
const struct x86_cpu_id *id;
+ struct cpu_defaults *cpu_info;
if (no_load)
return -ENODEV;
@@ -708,6 +755,11 @@ static int __init intel_pstate_init(void)
if (!id)
return -ENODEV;
+ cpu_info = (struct cpu_defaults *)id->driver_data;
+
+ copy_pid_params(&cpu_info->pid_policy);
+ copy_cpu_funcs(&cpu_info->funcs);
+
if (intel_pstate_msrs_not_valid())
return -ENODEV;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH 4/4] cpufreq/intel_pstate: Add Baytrail support
2013-10-21 16:20 [PATCH 0/4] intel_pstate updates dirk.brandewie
` (2 preceding siblings ...)
2013-10-21 16:20 ` [PATCH 3/4] cpufreq/intel_pstate: Refactor driver to support CPUs with different MSR layouts dirk.brandewie
@ 2013-10-21 16:20 ` dirk.brandewie
2013-10-21 16:29 ` [PATCH 0/4] intel_pstate updates Dirk Brandewie
4 siblings, 0 replies; 9+ messages in thread
From: dirk.brandewie @ 2013-10-21 16:20 UTC (permalink / raw)
To: linux-pm, rjw; +Cc: Dirk Brandewie
From: Dirk Brandewie <dirk.j.brandewie@intel.com>
Add support for the Baytrail processor
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
---
drivers/cpufreq/intel_pstate.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index c41fff9..89925513 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -33,6 +33,8 @@
#define SAMPLE_COUNT 3
+#define BYT_RATIOS 0x66a
+
#define FRAC_BITS 8
#define int_tofp(X) ((int64_t)(X) << FRAC_BITS)
#define fp_toint(X) ((X) >> FRAC_BITS)
@@ -341,6 +343,20 @@ static void intel_pstate_sysfs_expose_params(void)
}
/************************** sysfs end ************************/
+static int byt_get_min_pstate(void)
+{
+ u64 value;
+ rdmsrl(BYT_RATIOS, value);
+ return value & 0xFF;
+}
+
+static int byt_get_max_pstate(void)
+{
+ u64 value;
+ rdmsrl(BYT_RATIOS, value);
+ return (value >> 16) & 0xFF;
+}
+
static int core_get_min_pstate(void)
{
u64 value;
@@ -395,6 +411,24 @@ static struct cpu_defaults core_params = {
},
};
+static struct cpu_defaults byt_params = {
+ .pid_policy = {
+ .sample_rate_ms = 10,
+ .deadband = 0,
+ .setpoint = 97,
+ .p_gain_pct = 14,
+ .d_gain_pct = 0,
+ .i_gain_pct = 4,
+ },
+ .funcs = {
+ .get_max = byt_get_max_pstate,
+ .get_min = byt_get_min_pstate,
+ .get_turbo = byt_get_max_pstate,
+ .set = core_set_pstate,
+ },
+};
+
+
static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
{
int max_perf = cpu->pstate.turbo_pstate;
@@ -551,6 +585,7 @@ static void intel_pstate_timer_func(unsigned long __data)
static const struct x86_cpu_id intel_pstate_cpu_ids[] = {
ICPU(0x2a, core_params),
ICPU(0x2d, core_params),
+ ICPU(0x37, byt_params),
ICPU(0x3a, core_params),
ICPU(0x3c, core_params),
ICPU(0x3e, core_params),
--
1.8.3.1
^ permalink raw reply related [flat|nested] 9+ messages in thread