Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Thu, 16 Dec 2021 19:04:11 +0100 | Subject | Re: [PATCH v5 08/22] cpufreq: amd: introduce the support for the processors with shared memory solution |
| |
On Tue, Nov 30, 2021 at 1:38 PM Huang Rui <ray.huang@amd.com> wrote: > > In some of Zen2 and Zen3 based processors, they are using the shared > memory that exposed from ACPI SBIOS. In this kind of the processors, > there is no MSR support, so we add acpi cppc function as the backend for > them. > > It is using a module param (shared_mem) to enable related processors > manually. We will enable this by default once we address performance > issue on this solution. > > Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com> > Signed-off-by: Huang Rui <ray.huang@amd.com> > --- > drivers/cpufreq/amd-pstate.c | 72 ++++++++++++++++++++++++++++++++++-- > 1 file changed, 68 insertions(+), 4 deletions(-) > > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c > index cab266b8bf35..68991c450fd5 100644 > --- a/drivers/cpufreq/amd-pstate.c > +++ b/drivers/cpufreq/amd-pstate.c > @@ -35,6 +35,19 @@ > #define AMD_PSTATE_TRANSITION_LATENCY 0x20000 > #define AMD_PSTATE_TRANSITION_DELAY 500 > > +/* TODO: We need more time to fine tune processors with shared memory solution > + * with community together. > + * > + * There are some performance drops on the CPU benchmarks which reports from > + * Suse. We are co-working with them to fine tune the shared memory solution. So > + * we disable it by default to go acpi-cpufreq on these processors and add a > + * module parameter to be able to enable it manually for debugging. > + */ > +static bool shared_mem = false; > +module_param(shared_mem, bool, 0444); > +MODULE_PARM_DESC(shared_mem, > + "enable amd-pstate on processors with shared memory solution (false = disabled (default), true = enabled)"); > + > static struct cpufreq_driver amd_pstate_driver; > > struct amd_cpudata { > @@ -60,6 +73,19 @@ static inline int pstate_enable(bool enable) > return wrmsrl_safe(MSR_AMD_CPPC_ENABLE, enable); > } > > +static int cppc_enable(bool enable) > +{ > + int cpu, ret = 0; > + > + for_each_online_cpu(cpu) { > + ret = cppc_set_enable(cpu, enable); > + if (ret) > + return ret; > + } > + > + return ret; > +} > + > DEFINE_STATIC_CALL(amd_pstate_enable, pstate_enable); > > static inline int amd_pstate_enable(bool enable) > @@ -90,6 +116,24 @@ static int pstate_init_perf(struct amd_cpudata *cpudata) > return 0; > } > > +static int cppc_init_perf(struct amd_cpudata *cpudata) > +{ > + struct cppc_perf_caps cppc_perf; > + > + int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf); > + if (ret) > + return ret; > + > + WRITE_ONCE(cpudata->highest_perf, amd_get_highest_perf()); > + > + WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf); > + WRITE_ONCE(cpudata->lowest_nonlinear_perf, > + cppc_perf.lowest_nonlinear_perf); > + WRITE_ONCE(cpudata->lowest_perf, cppc_perf.lowest_perf); > + > + return 0; > +} > + > DEFINE_STATIC_CALL(amd_pstate_init_perf, pstate_init_perf); > > static inline int amd_pstate_init_perf(struct amd_cpudata *cpudata) > @@ -107,6 +151,19 @@ static void pstate_update_perf(struct amd_cpudata *cpudata, u32 min_perf, > READ_ONCE(cpudata->cppc_req_cached)); > } > > +static void cppc_update_perf(struct amd_cpudata *cpudata, > + u32 min_perf, u32 des_perf, > + u32 max_perf, bool fast_switch) > +{ > + struct cppc_perf_ctrls perf_ctrls; > + > + perf_ctrls.max_perf = max_perf; > + perf_ctrls.min_perf = min_perf; > + perf_ctrls.desired_perf = des_perf; > + > + cppc_set_perf(cpudata->cpu, &perf_ctrls); > +} > + > DEFINE_STATIC_CALL(amd_pstate_update_perf, pstate_update_perf); > > static inline void amd_pstate_update_perf(struct amd_cpudata *cpudata, > @@ -326,7 +383,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy) > /* It will be updated by governor */ > policy->cur = policy->cpuinfo.min_freq; > > - policy->fast_switch_possible = true; > + if (boot_cpu_has(X86_FEATURE_CPPC)) > + policy->fast_switch_possible = true; > > ret = freq_qos_add_request(&policy->constraints, &cpudata->req[0], > FREQ_QOS_MIN, policy->cpuinfo.min_freq); > @@ -376,7 +434,6 @@ static struct cpufreq_driver amd_pstate_driver = { > .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS, > .verify = amd_pstate_verify, > .target = amd_pstate_target, > - .adjust_perf = amd_pstate_adjust_perf, > .init = amd_pstate_cpu_init, > .exit = amd_pstate_cpu_exit, > .name = "amd-pstate", > @@ -399,8 +456,15 @@ static int __init amd_pstate_init(void) > return -EEXIST; > > /* capability check */ > - if (!boot_cpu_has(X86_FEATURE_CPPC)) { > - pr_debug("AMD CPPC MSR based functionality is not supported\n"); > + if (boot_cpu_has(X86_FEATURE_CPPC)) { > + pr_debug("AMD CPPC MSR based functionality is supported\n"); > + amd_pstate_driver.adjust_perf = amd_pstate_adjust_perf; > + } else if (shared_mem) { > + static_call_update(amd_pstate_enable, cppc_enable); > + static_call_update(amd_pstate_init_perf, cppc_init_perf); > + static_call_update(amd_pstate_update_perf, cppc_update_perf);
I would rather add the static call definitions in this patch, otherwise is somewhat cumbersome to review the series.
> + } else { > + pr_info("This processor supports shared memory solution, you can enable it with amd_pstate.shared_mem=1\n"); > return -ENODEV; > } > > -- > 2.25.1 >
| |