From: Paul Mackerras <paulus@samba.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf_counter: Prevent oopses from per-cpu software counters
Date: Fri, 6 Feb 2009 15:34:14 +1100 [thread overview]
Message-ID: <18827.48582.613391.869829@cargo.ozlabs.ibm.com> (raw)
In-Reply-To: <20090205142229.GB28443@elte.hu>
Ingo Molnar writes:
> So how about fixing these sw counts to properly work as percpu counters too?
OK, so for page faults it looks like I want to look at
get_cpu_var(vm_event_states).event[PGFAULT]
to get the per-cpu page fault count, as long as
CONFIG_VM_EVENT_COUNTERS is set.
It looks like the scheduler doesn't keep per-cpu counts of context
switches or task migrations, or if it does I couldn't find them. We
could do stuff in perf_counter_task_sched_in/out to implement per-cpu
context switch and migration counters by adding up the delta values
for each task that gets scheduled onto the cpu. Or we could add
explicit per-cpu counters for these things in the scheduler.
What do you think?
Paul.
next prev parent reply other threads:[~2009-02-06 4:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-05 4:52 Paul Mackerras
2009-02-05 14:22 ` Ingo Molnar
2009-02-06 2:40 ` Paul Mackerras
2009-02-06 4:34 ` Paul Mackerras [this message]
2009-02-06 6:35 ` Zhang, Yanmin
2009-02-06 15:31 ` Ingo Molnar
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