From: James Hogan <james.hogan@imgtec.com>
Date: Wed, 27 Feb 2013 16:16:38 +0000 (+0000)
Subject: metag: perf: add missing prev_count updates
X-Git-Tag: omap-for-v3.10/dt-fixes-for-merge-window~101^2~14
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c6ac1e6edacc7e1fb0405d61f95a797c6a712411;p=pandora-kernel.git

metag: perf: add missing prev_count updates

The prev_count needs setting when changing the counter value, otherwise
the calculated delta will be wrong, which for frequency sampling
(dynamic period sampling) results in sampling at too high a frequency.

For non-interrupting performance counters it should also be cleared when
enabling the counter since the write to the PERF_COUNT register will
clear the perf counter.

This also includes a minor change to remove the u64 cast from the
metag_pmu->write() call as metag_pmu->write() takes a u32 anyway, and in
any case GCC is smart enough to optimise away the cast.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
---

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