From 6378ddb592158db4b42197f1bc8666228800e379 Mon Sep 17 00:00:00 2001 From: Venki Pallipadi Date: Wed, 30 Jan 2008 13:30:04 +0100 Subject: time: track accurate idle time with tick_sched.idle_sleeptime Current idle time in kstat is based on jiffies and is coarse grained. tick_sched.idle_sleeptime is making some attempt to keep track of idle time in a fine grained manner. But, it is not handling the time spent in interrupts fully. Make tick_sched.idle_sleeptime accurate with respect to time spent on handling interrupts and also add tick_sched.idle_lastupdate, which keeps track of last time when idle_sleeptime was updated. This statistics will be crucial for cpufreq-ondemand governor, which can shed some conservative gaurd band that is uses today while setting the frequency. The ondemand changes that uses the exact idle time is coming soon. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/softirq.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel/softirq.c') diff --git a/kernel/softirq.c b/kernel/softirq.c index 8fe1ff40102..d7837d45419 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -280,9 +280,14 @@ asmlinkage void do_softirq(void) */ void irq_enter(void) { +#ifdef CONFIG_NO_HZ + int cpu = smp_processor_id(); + if (idle_cpu(cpu) && !in_interrupt()) + tick_nohz_stop_idle(cpu); +#endif __irq_enter(); #ifdef CONFIG_NO_HZ - if (idle_cpu(smp_processor_id())) + if (idle_cpu(cpu)) tick_nohz_update_jiffies(); #endif } -- cgit v1.2.3