linux-kernel - perf: is PERF_COUNT_SW_CONTEXT_SWITCHES a kernel or user event?

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Message-ID: <alpine.DEB.2.00.1106241658420.23095@cl320.eecs.utk.edu>
Date:	Fri, 24 Jun 2011 17:03:39 -0400 (EDT)
From:	Vince Weaver <vweaver1@...s.utk.edu>
To:	linux-kernel@...r.kernel.org
cc:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...e.hu>,
	Stephane Eranian <eranian@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>
Subject: perf: is PERF_COUNT_SW_CONTEXT_SWITCHES a kernel or user event?

Hello

the commit included in 2.6.34:
  perf: Use hot regs with software sched switch/migrate events
  e49a5bd38159dfb1928fd25b173bc9de4bbadb21

Changes the behavior of the PERF_COUNT_SW_CONTEXT_SWITCHES
counter.

Before 2.6.34 all of the PERF_COUNT_SW_CONTEXT_SWITCHES events were 
counted as happening in userspace (they show up in "perf stat -e cs:u") 
but after the commit they always happen in kernelspace ("perf stat -e 
cs:k").

Was this intended behavior?
I'm writing a validation test for this and want to make sure I get it
right.

This can be confusing if your tool defaults to userspace only counts (PAPI 
does this).

Thanks,

Vince
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