From e0be38ed4ab413ddd492118cf146369b86ee0ab5 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 23 Oct 2020 17:35:32 +0200 Subject: cpufreq: intel_pstate: Avoid missing HWP max updates in passive mode If the cpufreq policy max limit is changed when intel_pstate operates in the passive mode with HWP enabled and the "powersave" governor is used on top of it, the HWP max limit is not updated as appropriate. Namely, in the "powersave" governor case, the target P-state is always equal to the policy min limit, so if the latter does not change, intel_cpufreq_adjust_hwp() is not invoked to update the HWP Request MSR due to the "target_pstate != old_pstate" check in intel_cpufreq_update_pstate(), so the HWP max limit is not updated as a result. Also, if the CPUFREQ_NEED_UPDATE_LIMITS flag is not set for the driver and the target frequency does not change along with the policy max limit, the "target_freq == policy->cur" check in __cpufreq_driver_target() prevents the driver's ->target() callback from being invoked at all, so the HWP max limit is not updated. To prevent that occurring, set the CPUFREQ_NEED_UPDATE_LIMITS flag in the intel_cpufreq driver structure if HWP is enabled and modify intel_cpufreq_update_pstate() to do the "target_pstate != old_pstate" check only in the non-HWP case and let intel_cpufreq_adjust_hwp() always run in the HWP case (it will update HWP Request only if the cached value of the register is different from the new one including the limits, so if neither the target P-state value nor the max limit changes, the register write will still be avoided). Fixes: f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled") Reported-by: Zhang Rui Cc: 5.9+ # 5.9+: 1c534352f47f cpufreq: Introduce CPUFREQ_NEED_UPDATE_LIMITS ... Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Tested-by: Zhang Rui --- drivers/cpufreq/intel_pstate.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'drivers/cpufreq/intel_pstate.c') diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 3c1455518738..b7a9779250aa 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2568,14 +2568,12 @@ static int intel_cpufreq_update_pstate(struct cpudata *cpu, int target_pstate, int old_pstate = cpu->pstate.current_pstate; target_pstate = intel_pstate_prepare_request(cpu, target_pstate); - if (target_pstate != old_pstate) { + if (hwp_active) { + intel_cpufreq_adjust_hwp(cpu, target_pstate, fast_switch); + cpu->pstate.current_pstate = target_pstate; + } else if (target_pstate != old_pstate) { + intel_cpufreq_adjust_perf_ctl(cpu, target_pstate, fast_switch); cpu->pstate.current_pstate = target_pstate; - if (hwp_active) - intel_cpufreq_adjust_hwp(cpu, target_pstate, - fast_switch); - else - intel_cpufreq_adjust_perf_ctl(cpu, target_pstate, - fast_switch); } intel_cpufreq_trace(cpu, fast_switch ? INTEL_PSTATE_TRACE_FAST_SWITCH : @@ -3032,6 +3030,7 @@ static int __init intel_pstate_init(void) hwp_mode_bdw = id->driver_data; intel_pstate.attr = hwp_cpufreq_attrs; intel_cpufreq.attr = hwp_cpufreq_attrs; + intel_cpufreq.flags |= CPUFREQ_NEED_UPDATE_LIMITS; if (!default_driver) default_driver = &intel_pstate; -- cgit From fcb3a1ab79904d54499db77017793ccca665eb7e Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 10 Nov 2020 18:27:40 +0100 Subject: cpufreq: intel_pstate: Take CPUFREQ_GOV_STRICT_TARGET into account Make intel_pstate take the new CPUFREQ_GOV_STRICT_TARGET governor flag into account when it operates in the passive mode with HWP enabled, so as to fix the "powersave" governor behavior in that case (currently, HWP is allowed to scale the performance all the way up to the policy max limit when the "powersave" governor is used, but it should be constrained to the policy min limit then). Fixes: f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled") Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Cc: 5.9+ # 5.9+: 9a2a9ebc0a75 cpufreq: Introduce governor flags Cc: 5.9+ # 5.9+: 218f66870181 cpufreq: Introduce CPUFREQ_GOV_STRICT_TARGET Cc: 5.9+ # 5.9+: ea9364bbadf1 cpufreq: Add strict_target to struct cpufreq_policy --- drivers/cpufreq/intel_pstate.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'drivers/cpufreq/intel_pstate.c') diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index b7a9779250aa..36a3ccfe6d3d 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2527,7 +2527,7 @@ static void intel_cpufreq_trace(struct cpudata *cpu, unsigned int trace_type, in } static void intel_cpufreq_adjust_hwp(struct cpudata *cpu, u32 target_pstate, - bool fast_switch) + bool strict, bool fast_switch) { u64 prev = READ_ONCE(cpu->hwp_req_cached), value = prev; @@ -2539,7 +2539,7 @@ static void intel_cpufreq_adjust_hwp(struct cpudata *cpu, u32 target_pstate, * field in it, so opportunistically update the max too if needed. */ value &= ~HWP_MAX_PERF(~0L); - value |= HWP_MAX_PERF(cpu->max_perf_ratio); + value |= HWP_MAX_PERF(strict ? target_pstate : cpu->max_perf_ratio); if (value == prev) return; @@ -2562,14 +2562,16 @@ static void intel_cpufreq_adjust_perf_ctl(struct cpudata *cpu, pstate_funcs.get_val(cpu, target_pstate)); } -static int intel_cpufreq_update_pstate(struct cpudata *cpu, int target_pstate, - bool fast_switch) +static int intel_cpufreq_update_pstate(struct cpufreq_policy *policy, + int target_pstate, bool fast_switch) { + struct cpudata *cpu = all_cpu_data[policy->cpu]; int old_pstate = cpu->pstate.current_pstate; target_pstate = intel_pstate_prepare_request(cpu, target_pstate); if (hwp_active) { - intel_cpufreq_adjust_hwp(cpu, target_pstate, fast_switch); + intel_cpufreq_adjust_hwp(cpu, target_pstate, + policy->strict_target, fast_switch); cpu->pstate.current_pstate = target_pstate; } else if (target_pstate != old_pstate) { intel_cpufreq_adjust_perf_ctl(cpu, target_pstate, fast_switch); @@ -2609,7 +2611,7 @@ static int intel_cpufreq_target(struct cpufreq_policy *policy, break; } - target_pstate = intel_cpufreq_update_pstate(cpu, target_pstate, false); + target_pstate = intel_cpufreq_update_pstate(policy, target_pstate, false); freqs.new = target_pstate * cpu->pstate.scaling; @@ -2628,7 +2630,7 @@ static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy, target_pstate = DIV_ROUND_UP(target_freq, cpu->pstate.scaling); - target_pstate = intel_cpufreq_update_pstate(cpu, target_pstate, true); + target_pstate = intel_cpufreq_update_pstate(policy, target_pstate, true); return target_pstate * cpu->pstate.scaling; } -- cgit