Re: [PATCH v3 1/7] cpufreq: amd-pstate: initialize new core precision boost state

Oleksandr Natalenko
2024-02-07T15:11:10Z

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On středa 7. února 2024 15:45:20 CET Oleksandr Natalenko wrote:
> On středa 7. února 2024 10:21:52 CET Perry Yuan wrote:
> > From: Perry Yuan <Perry.Yuan@amd.com>
> >
> > Add gloal global_params to represent current CPU Performance Boost(cpb)
> > state for cpu frequency scaling, both active and passive modes all can
> > support CPU cores frequency boosting control which is based on the BIOS
> > setting, while BIOS turn on the "Core Performance Boost", it will
> > allow OS control each core highest perf limitation from OS side.
> >
> > If core performance boost is disabled while a core is in a boosted P-state,
> > the core transitions to the highest performance non-boosted P-state,
> > that is the same as the nominal frequency limit.
> >
> > Reported-by: Artem S. Tashkinov" <aros@gmx.com>
> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931
> > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> > ---
> > drivers/cpufreq/amd-pstate.c | 49 ++++++++++++------------------------
> > include/linux/amd-pstate.h | 14 +++++++++++
> > 2 files changed, 30 insertions(+), 33 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> > index 08e112444c27..3772f71f525f 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -67,6 +67,7 @@ static struct cpufreq_driver amd_pstate_epp_driver;
> > static int cppc_state = AMD_PSTATE_UNDEFINED;
> > static bool cppc_enabled;
> > static bool amd_pstate_prefcore = true;
> > +struct global_params global;
>
> Doesn't this require `EXPORT_SYMBOL_GPL(global)` then? Otherwise with v6.8 I get this:
>
> ```
> ERROR: modpost: "global" [drivers/cpufreq/amd-pstate-ut.ko] undefined!
> ```
>
> If so, I'd pretty mush rename this to be less generic, say, `amd_pstate_global_params_struct` for the struct name itself and `amd_pstate_global_params` for the actual variable name.

Something like this should do the trick (compile-tested only):

```
diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
index 91780ec42712..c5e2ca02f5ea 100644
--- a/drivers/cpufreq/amd-pstate-ut.c
+++ b/drivers/cpufreq/amd-pstate-ut.c
@@ -226,7 +226,7 @@ static void amd_pstate_ut_check_freq(u32 index)
goto skip_test;
}

- if (global.cpb_supported) {
+ if (amd_pstate_global_params.cpb_supported) {
if ((policy->max == cpudata->max_freq) ||
(policy->max == cpudata->nominal_freq))
amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS;
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index aebecd4e2e73..3e23d114c73f 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -68,7 +68,8 @@ static int cppc_state = AMD_PSTATE_UNDEFINED;
static bool cppc_enabled;
static bool amd_pstate_prefcore = true;
static struct quirk_entry *quirks;
-struct global_params global;
+struct amd_pstate_global_params amd_pstate_global_params;
+EXPORT_SYMBOL_GPL(amd_pstate_global_params);

/*
* AMD Energy Preference Performance (EPP)
@@ -496,7 +497,7 @@ static void amd_pstate_update(struct amd_cpudata *cpudata, u32 min_perf,
value |= AMD_CPPC_DES_PERF(des_perf);

/* limit the max perf when core performance boost feature is disabled */
- if (!global.cpb_boost)
+ if (!amd_pstate_global_params.cpb_boost)
max_perf = min_t(unsigned long, nominal_perf, max_perf);

value &= ~AMD_CPPC_MAX_PERF(~0L);
@@ -672,7 +673,7 @@ static int amd_get_max_freq(struct amd_cpudata *cpudata)
max_perf = READ_ONCE(cpudata->highest_perf);

/* when boost is off, the highest perf will be limited to nominal_perf */
- if (!global.cpb_boost)
+ if (!amd_pstate_global_params.cpb_boost)
max_perf = nominal_perf;

boost_ratio = div_u64(max_perf << SCHED_CAPACITY_SHIFT,
@@ -737,8 +738,8 @@ static int amd_pstate_boost_init(struct amd_cpudata *cpudata)
return ret;
}

- global.cpb_supported = !((boost_val >> 25) & 0x1);
- global.cpb_boost = global.cpb_supported;
+ amd_pstate_global_params.cpb_supported = !((boost_val >> 25) & 0x1);
+ amd_pstate_global_params.cpb_boost = amd_pstate_global_params.cpb_supported;

return ret;
}
@@ -1337,7 +1338,7 @@ static int amd_cpu_boost_update(struct amd_cpudata *cpudata, u32 on)
static ssize_t cpb_boost_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- return sysfs_emit(buf, "%u\n", global.cpb_boost);
+ return sysfs_emit(buf, "%u\n", amd_pstate_global_params.cpb_boost);
}

static ssize_t cpb_boost_store(struct device *dev, struct device_attribute *b,
@@ -1348,7 +1349,7 @@ static ssize_t cpb_boost_store(struct device *dev, struct device_attribute *b,
int cpu;

mutex_lock(&amd_pstate_driver_lock);
- if (!global.cpb_supported) {
+ if (!amd_pstate_global_params.cpb_supported) {
pr_err("Boost mode is not supported by this processor or SBIOS\n");
return -EINVAL;
}
@@ -1357,7 +1358,7 @@ static ssize_t cpb_boost_store(struct device *dev, struct device_attribute *b,
if (ret)
return -EINVAL;

- global.cpb_boost = !!new_state;
+ amd_pstate_global_params.cpb_boost = !!new_state;

for_each_possible_cpu(cpu) {

@@ -1371,7 +1372,7 @@ static ssize_t cpb_boost_store(struct device *dev, struct device_attribute *b,
goto err_exit;
}

- amd_cpu_boost_update(cpudata, global.cpb_boost);
+ amd_cpu_boost_update(cpudata, amd_pstate_global_params.cpb_boost);
refresh_frequency_limits(policy);
cpufreq_cpu_put(policy);
}
diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
index b0db335f3883..f6e2c9825700 100644
--- a/include/linux/amd-pstate.h
+++ b/include/linux/amd-pstate.h
@@ -129,16 +129,16 @@ struct quirk_entry {
};

/**
- * struct global_params - Global parameters, mostly tunable via sysfs.
+ * struct amd_pstate_global_params - Global parameters, mostly tunable via sysfs.
* @cpb_boost: Whether or not to use boost CPU P-states.
* @cpb_supported: Whether or not CPU boost P-states are available
* based on the MSR_K7_HWCR bit[25] state
*/
-struct global_params {
+struct amd_pstate_global_params {
bool cpb_boost;
bool cpb_supported;
};

-extern struct global_params global;
+extern struct amd_pstate_global_params amd_pstate_global_params;

#endif /* _LINUX_AMD_PSTATE_H */
```

> >
> > /*
> > * AMD Energy Preference Performance (EPP)
> > @@ -669,43 +670,21 @@ static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
> > return lowest_nonlinear_freq * 1000;
> > }
> >
> > -static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
> > +static int amd_pstate_boost_init(struct amd_cpudata *cpudata)
> > {
> > - struct amd_cpudata *cpudata = policy->driver_data;
> > + u64 boost_val;
> > int ret;
> >
> > - if (!cpudata->boost_supported) {
> > - pr_err("Boost mode is not supported by this processor or SBIOS\n");
> > - return -EINVAL;
> > - }
> > -
> > - if (state)
> > - policy->cpuinfo.max_freq = cpudata->max_freq;
> > - else
> > - policy->cpuinfo.max_freq = cpudata->nominal_freq;
> > -
> > - policy->max = policy->cpuinfo.max_freq;
> > -
> > - ret = freq_qos_update_request(&cpudata->req[1],
> > - policy->cpuinfo.max_freq);
> > - if (ret < 0)
> > + ret = rdmsrl_on_cpu(cpudata->cpu, MSR_K7_HWCR, &boost_val);
> > + if (ret) {
> > + pr_err_once("failed to read initial CPU boost state!\n");
> > return ret;
> > + }
> >
> > - return 0;
> > -}
> > -
> > -static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
> > -{
> > - u32 highest_perf, nominal_perf;
> > -
> > - highest_perf = READ_ONCE(cpudata->highest_perf);
> > - nominal_perf = READ_ONCE(cpudata->nominal_perf);
> > -
> > - if (highest_perf <= nominal_perf)
> > - return;
> > + global.cpb_supported = !((boost_val >> 25) & 0x1);
> > + global.cpb_boost = global.cpb_supported;
> >
> > - cpudata->boost_supported = true;
> > - current_pstate_driver->boost_enabled = true;
> > + return ret;
> > }
> >
> > static void amd_perf_ctl_reset(unsigned int cpu)
> > @@ -848,6 +827,9 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> > if (ret)
> > goto free_cpudata1;
> >
> > + /* initialize cpu cores boot state */
> > + amd_pstate_boost_init(cpudata);
> > +
> > min_freq = amd_get_min_freq(cpudata);
> > max_freq = amd_get_max_freq(cpudata);
> > nominal_freq = amd_get_nominal_freq(cpudata);
> > @@ -899,7 +881,6 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> >
> > policy->driver_data = cpudata;
> >
> > - amd_pstate_boost_init(cpudata);
> > if (!current_pstate_driver->adjust_perf)
> > current_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
> >
> > @@ -1310,6 +1291,9 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
> > if (ret)
> > goto free_cpudata1;
> >
> > + /* initialize cpu cores boot state */
> > + amd_pstate_boost_init(cpudata);
> > +
> > min_freq = amd_get_min_freq(cpudata);
> > max_freq = amd_get_max_freq(cpudata);
> > nominal_freq = amd_get_nominal_freq(cpudata);
> > @@ -1360,7 +1344,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
> > return ret;
> > WRITE_ONCE(cpudata->cppc_cap1_cached, value);
> > }
> > - amd_pstate_boost_init(cpudata);
> >
> > return 0;
> >
> > diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> > index d21838835abd..465e9295a60c 100644
> > --- a/include/linux/amd-pstate.h
> > +++ b/include/linux/amd-pstate.h
> > @@ -124,4 +124,18 @@ static const char * const amd_pstate_mode_string[] = {
> > [AMD_PSTATE_GUIDED] = "guided",
> > NULL,
> > };
> > +
> > +/**
> > + * struct global_params - Global parameters, mostly tunable via sysfs.
> > + * @cpb_boost: Whether or not to use boost CPU P-states.
> > + * @cpb_supported: Whether or not CPU boost P-states are available
> > + * based on the MSR_K7_HWCR bit[25] state
> > + */
> > +struct global_params {
> > + bool cpb_boost;
> > + bool cpb_supported;
> > +};
> > +
> > +extern struct global_params global;
> > +
> > #endif /* _LINUX_AMD_PSTATE_H */
> >
>
>
>

--
Oleksandr Natalenko (post-factum)

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