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authorJames Hogan <james.hogan@imgtec.com>2013-02-27 21:54:51 +0000
committerJames Hogan <james.hogan@imgtec.com>2013-03-15 13:20:15 +0000
commit1fb4dc5c39af941d3abc597337e0ea776bfce0f2 (patch)
tree3a5a08501b8f421de3d69263c0bad38bd95221d1 /arch/metag/kernel/perf
parent9344de1b1c64b2217f3b15508266deff2a8d6c84 (diff)
metag: perf: don't reset TXTACTCYC
The thread active cycle counter TXTACTCYC is used in __delay so it shouldn't really be reset to zero by perf. Fix perf to just read the value, and instead of clearing it, record the prev_count value in enable_counter so that the delta calculations know about the previous value. 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>
Diffstat (limited to 'arch/metag/kernel/perf')
-rw-r--r--arch/metag/kernel/perf/perf_event.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/arch/metag/kernel/perf/perf_event.c b/arch/metag/kernel/perf/perf_event.c
index 54fde35b4b9c..a1eff3687e8e 100644
--- a/arch/metag/kernel/perf/perf_event.c
+++ b/arch/metag/kernel/perf/perf_event.c
@@ -617,9 +617,7 @@ static void metag_pmu_enable_counter(struct hw_perf_event *event, int idx)
WARN_ONCE((config != 0x100),
"invalid configuration (%d) for counter (%d)\n",
config, idx);
-
- /* Reset the cycle count */
- __core_reg_set(TXTACTCYC, 0);
+ local64_set(&event->prev_count, __core_reg_get(TXTACTCYC));
goto unlock;
}
@@ -708,9 +706,8 @@ static u64 metag_pmu_read_counter(int idx)
{
u32 tmp = 0;
- /* The act of reading the cycle counter also clears it */
if (METAG_INST_COUNTER == idx) {
- __core_reg_swap(TXTACTCYC, tmp);
+ tmp = __core_reg_get(TXTACTCYC);
goto out;
}