On 6/20/13 12:47 PM, Steven Rostedt wrote:
On Thu, 2013-06-20 at 12:35 -0600, David Ahern wrote:
On 6/20/13 12:23 PM, Steven Rostedt wrote:
I ran this:
perf stat --repeat 100 -- perf bench sched pipe >
/tmp/perf-bench-sched.{before, after}
You want to compare:
perf stat --repeat 100 -p 1 -- perf bench sched pipe
so that event is tagged to pid 1 and not the perf-bench workload.
I guess I'm a bit confused. What's the significance of measuring pid 1
(init)?
I believe Oleg's point is the overhead for tasks without events
associated with them. To show that create an event tagged to the init
task and then run some workload -- like perf bench shed pipe. It shows
that all tasks take a hit, not just the one getting profiled.
David
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