[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] cpufreq: Short path avoiding IPI in critical fast path.
# HG changeset patch # User Keir Fraser <keir.fraser@xxxxxxxxxx> # Date 1228994869 0 # Node ID 0f1a166fe92e489d0b5e3d3d35bcdb004b20f0eb # Parent 147c646a28361b19326fc90de79dbbcb7ab83613 cpufreq: Short path avoiding IPI in critical fast path. Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx> Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx> --- xen/arch/x86/acpi/cpufreq/cpufreq.c | 22 ++++++++++++++++------ 1 files changed, 16 insertions(+), 6 deletions(-) diff -r 147c646a2836 -r 0f1a166fe92e xen/arch/x86/acpi/cpufreq/cpufreq.c --- a/xen/arch/x86/acpi/cpufreq/cpufreq.c Thu Dec 11 11:19:27 2008 +0000 +++ b/xen/arch/x86/acpi/cpufreq/cpufreq.c Thu Dec 11 11:27:49 2008 +0000 @@ -255,17 +255,27 @@ static void __get_measured_perf(void *p static unsigned int get_measured_perf(unsigned int cpu) { - unsigned int retval, perf_percent; + struct cpufreq_policy *policy; + unsigned int perf_percent; cpumask_t cpumask; if (!cpu_online(cpu)) return 0; - cpumask = cpumask_of_cpu(cpu); - on_selected_cpus(cpumask, __get_measured_perf, (void *)&perf_percent,0,1); - - retval = drv_data[cpu]->max_freq * perf_percent / 100; - return retval; + policy = cpufreq_cpu_policy[cpu]; + if (!policy) + return 0; + + /* Usually we take the short path (no IPI) for the sake of performance. */ + if (cpu == smp_processor_id()) { + __get_measured_perf((void *)&perf_percent); + } else { + cpumask = cpumask_of_cpu(cpu); + on_selected_cpus(cpumask, __get_measured_perf, + (void *)&perf_percent,0,1); + } + + return drv_data[cpu]->max_freq * perf_percent / 100; } static unsigned int get_cur_freq_on_cpu(unsigned int cpu) _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
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