Messages in this thread | | | Date | Fri, 17 Dec 2021 15:37:43 +0800 | From | Huang Rui <> | Subject | Re: [PATCH v5 08/22] cpufreq: amd: introduce the support for the processors with shared memory solution |
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On Fri, Dec 17, 2021 at 02:04:11AM +0800, Rafael J. Wysocki wrote: > 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. >
I see. Will move them into this patch in V6.
Thanks, Ray
> > + } 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 > >
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