From a97e293e077a3e8f41e8972e593b34d0052b9e25 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 4 Nov 2024 19:51:28 +0100 Subject: [PATCH 1/2] cpufreq: intel_pstate: Clear hybrid_max_perf_cpu before driver registration Modify intel_pstate_register_driver() to clear hybrid_max_perf_cpu before calling cpufreq_register_driver(), so that asymmetric CPU capacity scaling is not updated until hybrid_init_cpu_capacity_scaling() runs down the road. This is done in preparation for a subsequent change adding asymmetric CPU capacity computation to the CPU init path to handle CPUs that are initially offline. The information on whether or not hybrid_max_perf_cpu was NULL before it has been cleared is passed to hybrid_init_cpu_capacity_scaling(), so full initialization of CPU capacity scaling can be skipped if it has been carried out already. No intentional functional impact. Signed-off-by: Rafael J. Wysocki Link: https://patch.msgid.link/4616631.LvFx2qVVIh@rjwysocki.net --- drivers/cpufreq/intel_pstate.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index b0018f371ea3a..4e816f0857f24 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1034,7 +1034,7 @@ static void __hybrid_init_cpu_capacity_scaling(void) hybrid_update_cpu_capacity_scaling(); } -static void hybrid_init_cpu_capacity_scaling(void) +static void hybrid_init_cpu_capacity_scaling(bool refresh) { bool disable_itmt = false; @@ -1045,7 +1045,7 @@ static void hybrid_init_cpu_capacity_scaling(void) * scaling has been enabled already and the driver is just changing the * operation mode. */ - if (hybrid_max_perf_cpu) { + if (refresh) { __hybrid_init_cpu_capacity_scaling(); goto unlock; } @@ -1071,6 +1071,18 @@ static void hybrid_init_cpu_capacity_scaling(void) sched_clear_itmt_support(); } +static bool hybrid_clear_max_perf_cpu(void) +{ + bool ret; + + guard(mutex)(&hybrid_capacity_lock); + + ret = !!hybrid_max_perf_cpu; + hybrid_max_perf_cpu = NULL; + + return ret; +} + static void __intel_pstate_get_hwp_cap(struct cpudata *cpu) { u64 cap; @@ -3352,6 +3364,7 @@ static void intel_pstate_driver_cleanup(void) static int intel_pstate_register_driver(struct cpufreq_driver *driver) { + bool refresh_cpu_cap_scaling; int ret; if (driver == &intel_pstate) @@ -3364,6 +3377,8 @@ static int intel_pstate_register_driver(struct cpufreq_driver *driver) arch_set_max_freq_ratio(global.turbo_disabled); + refresh_cpu_cap_scaling = hybrid_clear_max_perf_cpu(); + intel_pstate_driver = driver; ret = cpufreq_register_driver(intel_pstate_driver); if (ret) { @@ -3373,7 +3388,7 @@ static int intel_pstate_register_driver(struct cpufreq_driver *driver) global.min_perf_pct = min_perf_pct_min(); - hybrid_init_cpu_capacity_scaling(); + hybrid_init_cpu_capacity_scaling(refresh_cpu_cap_scaling); return 0; } From 92447aa5f6e7fbad9427a3fd1bb9e0679c403206 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Mon, 4 Nov 2024 19:53:53 +0100 Subject: [PATCH 2/2] cpufreq: intel_pstate: Update asym capacity for CPUs that were offline initially Commit 929ebc93ccaa ("cpufreq: intel_pstate: Set asymmetric CPU capacity on hybrid systems") overlooked a corner case in which some CPUs may be offline to start with and brought back online later, after the intel_pstate driver has been registered, so their asymmetric capacity will not be set. Address this by calling hybrid_update_capacity() in the CPU initialization path that is executed instead of the online path for those CPUs. Note that this asymmetric capacity update will be skipped during driver initialization and mode switches because hybrid_max_perf_cpu is NULL in those cases. Fixes: 929ebc93ccaa ("cpufreq: intel_pstate: Set asymmetric CPU capacity on hybrid systems") Signed-off-by: Rafael J. Wysocki Link: https://patch.msgid.link/1913414.tdWV9SEqCh@rjwysocki.net --- drivers/cpufreq/intel_pstate.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 4e816f0857f24..cd2ac1ba53d2a 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2275,6 +2275,11 @@ static void intel_pstate_get_cpu_pstates(struct cpudata *cpu) } else { cpu->pstate.scaling = perf_ctl_scaling; } + /* + * If the CPU is going online for the first time and it was + * offline initially, asym capacity scaling needs to be updated. + */ + hybrid_update_capacity(cpu); } else { cpu->pstate.scaling = perf_ctl_scaling; cpu->pstate.max_pstate = pstate_funcs.get_max(cpu->cpu);