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| author | Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> | 2009-04-06 11:26:08 -0700 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2009-04-07 18:15:05 -0400 |
| commit | 18b2646fe3babeb40b34a0c1751e0bf5adfdc64c (patch) | |
| tree | 544fd1676479f609a9b307365374e44c697a44f5 /arch/x86/kernel | |
| parent | e4f6937222dbb61b8b8e62caca3d32e648b3b14b (diff) | |
| download | lwn-18b2646fe3babeb40b34a0c1751e0bf5adfdc64c.tar.gz lwn-18b2646fe3babeb40b34a0c1751e0bf5adfdc64c.zip | |
ACPI x86: Make aperf/mperf MSR access in acpi_cpufreq read_only
Do not write zeroes to APERF and MPERF by ondemand governor. With this
change, other users can share these MSRs for reads.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c index 340bdbebba07..9d3af380c6bd 100644 --- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c +++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c @@ -68,6 +68,7 @@ struct acpi_cpufreq_data { unsigned int max_freq; unsigned int resume; unsigned int cpu_feature; + u64 saved_aperf, saved_mperf; }; static DEFINE_PER_CPU(struct acpi_cpufreq_data *, drv_data); @@ -259,9 +260,6 @@ static long read_measured_perf_ctrs(void *_cur) rdmsr(MSR_IA32_APERF, cur->aperf.split.lo, cur->aperf.split.hi); rdmsr(MSR_IA32_MPERF, cur->mperf.split.lo, cur->mperf.split.hi); - wrmsr(MSR_IA32_APERF, 0, 0); - wrmsr(MSR_IA32_MPERF, 0, 0); - return 0; } @@ -281,13 +279,20 @@ static long read_measured_perf_ctrs(void *_cur) static unsigned int get_measured_perf(struct cpufreq_policy *policy, unsigned int cpu) { - struct perf_pair cur; + struct perf_pair readin, cur; unsigned int perf_percent; unsigned int retval; - if (!work_on_cpu(cpu, read_measured_perf_ctrs, &cur)) + if (!work_on_cpu(cpu, read_measured_perf_ctrs, &readin)) return 0; + cur.aperf.whole = readin.aperf.whole - + per_cpu(drv_data, cpu)->saved_aperf; + cur.mperf.whole = readin.mperf.whole - + per_cpu(drv_data, cpu)->saved_mperf; + per_cpu(drv_data, cpu)->saved_aperf = readin.aperf.whole; + per_cpu(drv_data, cpu)->saved_mperf = readin.mperf.whole; + #ifdef __i386__ /* * We dont want to do 64 bit divide with 32 bit kernel |