On Fri, 2013-12-06 at 16:46 -0800, Andi Kleen wrote: > From: Andi Kleen <[email protected]> > > This patch creates 4 new trace points: one at the beginning of idle, > one before entering mwait, one after exiting mwait, and one after > finishing the idle code. This is useful to trace down any > additional latencies caused by the ever-growing idle code. > > Idle latencies are a common source of performance problems, so it's > important to be able to measure them.
You mean stuff like.. oh, say 60 cores doing zero work every 12ms
munching ~20% cpu?
- 97.57% [kernel] [k] _raw_spin_lock_irqsave
▒
- _raw_spin_lock_irqsave
▒
- 97.02% clockevents_notify
◆
intel_idle
▒
cpuidle_idle_call
▒
cpu_idle
▒
- 2.97% tick_broadcast_oneshot_control
▒
tick_notify
▒
notifier_call_chain
▒
clockevents_notify
▒
intel_idle
▒
cpuidle_idle_call
▒
cpu_idle
C2 is super green, it's hug'n the sh*t outta them trees :)
-Mike
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