Messages in this thread Patch in this message | | | From | Huang Rui <> | Subject | [PATCH v4 07/22] cpufreq: amd: add fast switch function for amd-pstate | Date | Fri, 19 Nov 2021 18:30:47 +0800 |
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Introduce the fast switch function for amd-pstate on the AMD processors which support the full MSR register control. It's able to decrease the latency on interrupt context.
Signed-off-by: Huang Rui <ray.huang@amd.com> --- drivers/cpufreq/amd-pstate.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c index 8b501a72c3dd..4a02a42f4113 100644 --- a/drivers/cpufreq/amd-pstate.c +++ b/drivers/cpufreq/amd-pstate.c @@ -177,6 +177,38 @@ static int amd_pstate_target(struct cpufreq_policy *policy, return 0; } +static void amd_pstate_adjust_perf(unsigned int cpu, + unsigned long _min_perf, + unsigned long target_perf, + unsigned long capacity) +{ + unsigned long max_perf, min_perf, des_perf, + cap_perf, lowest_nonlinear_perf; + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + struct amd_cpudata *cpudata = policy->driver_data; + + cap_perf = READ_ONCE(cpudata->highest_perf); + lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf); + + if (target_perf < capacity) + des_perf = DIV_ROUND_UP(cap_perf * target_perf, capacity); + + min_perf = READ_ONCE(cpudata->highest_perf); + if (_min_perf < capacity) + min_perf = DIV_ROUND_UP(cap_perf * _min_perf, capacity); + + if (min_perf < lowest_nonlinear_perf) + min_perf = lowest_nonlinear_perf; + + max_perf = cap_perf; + if (max_perf < min_perf) + max_perf = min_perf; + + des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf); + + amd_pstate_update(cpudata, min_perf, des_perf, max_perf, true); +} + static int amd_get_min_freq(struct amd_cpudata *cpudata) { struct cppc_perf_caps cppc_perf; @@ -293,6 +325,8 @@ 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; + ret = freq_qos_add_request(&policy->constraints, &cpudata->req[0], FREQ_QOS_MIN, policy->cpuinfo.min_freq); if (ret < 0) { @@ -341,6 +375,7 @@ 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", -- 2.25.1
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