From cb85a6ed67e979c59a29b7b4e8217e755b951cf4 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Fri, 30 Mar 2012 12:23:08 +0200 Subject: proc: stats: Use arch_idle_time for idle and iowait times if available Git commit a25cac5198d4ff28 "proc: Consider NO_HZ when printing idle and iowait times" changes the code for /proc/stat to use get_cpu_idle_time_us and get_cpu_iowait_time_us if the system is running with nohz enabled. For architectures which define arch_idle_time (currently s390 only) this is a change for the worse. The result of arch_idle_time is supposed to be the exact sleep time of the target cpu and should be used instead of the value kept by the scheduler. Signed-off-by: Martin Schwidefsky Reviewed-by: Michal Hocko Reviewed-by: Srivatsa S. Bhat Link: http://lkml.kernel.org/r/20120330122308.18720283@de.ibm.com Signed-off-by: Thomas Gleixner --- fs/proc/stat.c | 34 ++++++++++++++++++++++++++++------ 1 file changed, 28 insertions(+), 6 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/stat.c b/fs/proc/stat.c index 6a0c62d6e44..64c3b317236 100644 --- a/fs/proc/stat.c +++ b/fs/proc/stat.c @@ -18,19 +18,39 @@ #ifndef arch_irq_stat #define arch_irq_stat() 0 #endif -#ifndef arch_idle_time -#define arch_idle_time(cpu) 0 -#endif + +#ifdef arch_idle_time + +static cputime64_t get_idle_time(int cpu) +{ + cputime64_t idle; + + idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE]; + if (cpu_online(cpu) && !nr_iowait_cpu(cpu)) + idle += arch_idle_time(cpu); + return idle; +} + +static cputime64_t get_iowait_time(int cpu) +{ + cputime64_t iowait; + + iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT]; + if (cpu_online(cpu) && nr_iowait_cpu(cpu)) + iowait += arch_idle_time(cpu); + return iowait; +} + +#else static u64 get_idle_time(int cpu) { u64 idle, idle_time = get_cpu_idle_time_us(cpu, NULL); - if (idle_time == -1ULL) { + if (idle_time == -1ULL) /* !NO_HZ so we can rely on cpustat.idle */ idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE]; - idle += arch_idle_time(cpu); - } else + else idle = usecs_to_cputime64(idle_time); return idle; @@ -49,6 +69,8 @@ static u64 get_iowait_time(int cpu) return iowait; } +#endif + static int show_stat(struct seq_file *p, void *v) { int i, j; -- cgit v1.2.3