[PATCH] trace power_frequency events on the correct cpu (for Intel x86 CPUs)

Robert Schöne
2010-03-12T13:18:12Z

This patch fixes the following behaviour:
Currently, the power_frequency event is reported for the cpu (core) which initiated the frequency change.
It should be reported for the cpu that actually changes its frequency.

Example: when using
taskset -c 0 echo <new_frequency> > /sys/devices/system/cpu/cpu1/cpufreq/scaling_setspeed
cpu 0 is traced, instead of cpu 1

Signed of by Robert Schoene <robert.schoene@tu-dresden.de>

diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
index 1b1920f..0a47f10 100644
--- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -174,6 +174,7 @@ static void do_drv_write(void *_cmd)

switch (cmd->type) {
case SYSTEM_INTEL_MSR_CAPABLE:
+ trace_power_frequency(POWER_PSTATE, cmd->val);
rdmsr(cmd->addr.msr.reg, lo, hi);
lo = (lo & ~INTEL_MSR_RANGE) | (cmd->val & INTEL_MSR_RANGE);
wrmsr(cmd->addr.msr.reg, lo, hi);
@@ -363,7 +364,6 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy,
}
}

- trace_power_frequency(POWER_PSTATE, data->freq_table[next_state].frequency);

switch (data->cpu_feature) {