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authorVenki Pallipadi <venkatesh.pallipadi@intel.com>2008-01-30 13:30:04 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:30:04 +0100
commit6378ddb592158db4b42197f1bc8666228800e379 (patch)
treef9b1e671dfd12fb221f6140dd231ccb14cd9f27e /kernel/softirq.c
parentbbe4d18ac2e058c56adb0cd71f49d9ed3216a405 (diff)
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 <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/softirq.c')
-rw-r--r--kernel/softirq.c7
1 files changed, 6 insertions, 1 deletions
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
}