hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I73EPL
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As ARM AMU's document says, all counters are subject to any changes in clock frequency, including clock stopping caused by the WFI and WFE instructions.
Therefore, using smp_call_on_cpu() to trigger target CPU to read self's AMU counters, which ensures the counters are working properly while cstate feature is enabled.
Reported-by: Sumit Gupta sumitg@nvidia.com Link: https://lore.kernel.org/all/20230418113459.12860-7-sumitg@nvidia.com/ Signed-off-by: Zeng Heng zengheng4@huawei.com --- drivers/cpufreq/cppc_cpufreq.c | 39 ++++++++++++++++++++++++++-------- 1 file changed, 30 insertions(+), 9 deletions(-)
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c index fe08ca419b3d..321a9dc9484d 100644 --- a/drivers/cpufreq/cppc_cpufreq.c +++ b/drivers/cpufreq/cppc_cpufreq.c @@ -90,6 +90,12 @@ static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data, struct cppc_perf_fb_ctrs *fb_ctrs_t0, struct cppc_perf_fb_ctrs *fb_ctrs_t1);
+struct fb_ctr_pair { + u32 cpu; + struct cppc_perf_fb_ctrs fb_ctrs_t0; + struct cppc_perf_fb_ctrs fb_ctrs_t1; +}; + /** * cppc_scale_freq_workfn - CPPC arch_freq_scale updater for frequency invariance * @work: The work item. @@ -840,9 +846,24 @@ static int cppc_perf_from_fbctrs(struct cppc_cpudata *cpu_data, return (reference_perf * delta_delivered) / delta_reference; }
+static int cppc_get_perf_ctrs_pair(void *val) +{ + struct fb_ctr_pair *fb_ctrs = val; + int cpu = fb_ctrs->cpu; + int ret; + + ret = cppc_get_perf_ctrs(cpu, &fb_ctrs->fb_ctrs_t0); + if (ret) + return ret; + + udelay(2); /* 2usec delay between sampling */ + + return cppc_get_perf_ctrs(cpu, &fb_ctrs->fb_ctrs_t1); +} + static unsigned int cppc_cpufreq_get_rate(unsigned int cpu) { - struct cppc_perf_fb_ctrs fb_ctrs_t0 = {0}, fb_ctrs_t1 = {0}; + struct fb_ctr_pair fb_ctrs = { .cpu = cpu, }; struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); struct cppc_cpudata *cpu_data = policy->driver_data; u64 delivered_perf; @@ -850,18 +871,18 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
cpufreq_cpu_put(policy);
- ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t0); - if (ret) - return 0; - - udelay(2); /* 2usec delay between sampling */ + if (cpu_has_amu_feat(cpu)) + ret = smp_call_on_cpu(cpu, cppc_get_perf_ctrs_pair, + &fb_ctrs, false); + else + ret = cppc_get_perf_ctrs_pair(&fb_ctrs);
- ret = cppc_get_perf_ctrs(cpu, &fb_ctrs_t1); if (ret) return 0;
- delivered_perf = cppc_perf_from_fbctrs(cpu_data, &fb_ctrs_t0, - &fb_ctrs_t1); + delivered_perf = cppc_perf_from_fbctrs(cpu_data, + &fb_ctrs.fb_ctrs_t0, + &fb_ctrs.fb_ctrs_t1);
return cppc_cpufreq_perf_to_khz(cpu_data, delivered_perf); }