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authorVenkatesh Pallipadi <venki@google.com>2010-10-05 04:03:19 +0400
committerIngo Molnar <mingo@elte.hu>2010-10-18 22:52:24 +0400
commitb52bfee445d315549d41eacf2fa7c156e7d153d5 (patch)
tree740f3aa24e2afad42772a662ceb460c555003c0f /include/linux
parent6cdd5199daf0cb7b0fcc8dca941af08492612887 (diff)
downloadlinux-b52bfee445d315549d41eacf2fa7c156e7d153d5.tar.xz
sched: Add IRQ_TIME_ACCOUNTING, finer accounting of irq time
s390/powerpc/ia64 have support for CONFIG_VIRT_CPU_ACCOUNTING which does the fine granularity accounting of user, system, hardirq, softirq times. Adding that option on archs like x86 will be challenging however, given the state of TSC reliability on various platforms and also the overhead it will add in syscall entry exit. Instead, add a lighter variant that only does finer accounting of hardirq and softirq times, providing precise irq times (instead of timer tick based samples). This accounting is added with a new config option CONFIG_IRQ_TIME_ACCOUNTING so that there won't be any overhead for users not interested in paying the perf penalty. This accounting is based on sched_clock, with the code being generic. So, other archs may find it useful as well. This patch just adds the core logic and does not enable this logic yet. Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1286237003-12406-5-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/hardirq.h2
-rw-r--r--include/linux/sched.h13
2 files changed, 14 insertions, 1 deletions
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 41367c5c3c68..ff43e9268449 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -137,7 +137,7 @@ extern void synchronize_irq(unsigned int irq);
struct task_struct;
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
+#if !defined(CONFIG_VIRT_CPU_ACCOUNTING) && !defined(CONFIG_IRQ_TIME_ACCOUNTING)
static inline void account_system_vtime(struct task_struct *tsk)
{
}
diff --git a/include/linux/sched.h b/include/linux/sched.h
index aca0ce675939..2cca9a92f5e5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1826,6 +1826,19 @@ extern void sched_clock_idle_sleep_event(void);
extern void sched_clock_idle_wakeup_event(u64 delta_ns);
#endif
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+/*
+ * An i/f to runtime opt-in for irq time accounting based off of sched_clock.
+ * The reason for this explicit opt-in is not to have perf penalty with
+ * slow sched_clocks.
+ */
+extern void enable_sched_clock_irqtime(void);
+extern void disable_sched_clock_irqtime(void);
+#else
+static inline void enable_sched_clock_irqtime(void) {}
+static inline void disable_sched_clock_irqtime(void) {}
+#endif
+
extern unsigned long long
task_sched_runtime(struct task_struct *task);
extern unsigned long long thread_group_sched_runtime(struct task_struct *task);