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| author | Tom Huynh <tom.huynh@freescale.com> | 2015-01-20 22:19:50 (GMT) |
|---|---|---|
| committer | Honghua Yin <Hong-Hua.Yin@freescale.com> | 2015-04-16 00:21:52 (GMT) |
| commit | b1540b070f540430c553be5fdfa3b9edbf60ec7e (patch) | |
| tree | f4e0adb1807505bd738225ed0fae27e68e35a547 /arch | |
| parent | acc6b9b8ac4546066221f6ad0e57310ad3a9ba50 (diff) | |
| download | linux-fsl-qoriq-b1540b070f540430c553be5fdfa3b9edbf60ec7e.tar.xz | |
powerpc/perf: fix fsl_emb_pmu_start to write correct pmc value
PMCs on PowerPC increases towards 0x80000000 and triggers an overflow
interrupt when the msb is set to collect a sample. Therefore, to setup
for the next sample collection, pmu_start should set the pmc value to
0x80000000 - left instead of left which incorrectly delays the next
overflow interrupt. Same as commit 9a45a9407c69 ("powerpc/perf:
power_pmu_start restores incorrect values, breaking frequency events")
for book3s.
Signed-off-by: Tom Huynh <tom.huynh@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
(cherry picked from commit d2caa3cebda8b626336e100b80a0ed6f909dccab)
Change-Id: I2179f49218e1e0cd836c67714430a86be8535a27
Reviewed-on: http://git.am.freescale.net:8181/35052
Reviewed-by: Richard Schmitt <richard.schmitt@freescale.com>
Tested-by: Review Code-CDREVIEW <CDREVIEW@freescale.com>
Reviewed-by: Honghua Yin <Hong-Hua.Yin@freescale.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/perf/core-fsl-emb.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/powerpc/perf/core-fsl-emb.c b/arch/powerpc/perf/core-fsl-emb.c index d35ae52..6e92050 100644 --- a/arch/powerpc/perf/core-fsl-emb.c +++ b/arch/powerpc/perf/core-fsl-emb.c @@ -389,6 +389,7 @@ static void fsl_emb_pmu_del(struct perf_event *event, int flags) static void fsl_emb_pmu_start(struct perf_event *event, int ef_flags) { unsigned long flags; + unsigned long val; s64 left; if (event->hw.idx < 0 || !event->hw.sample_period) @@ -405,7 +406,10 @@ static void fsl_emb_pmu_start(struct perf_event *event, int ef_flags) event->hw.state = 0; left = local64_read(&event->hw.period_left); - write_pmc(event->hw.idx, left); + val = 0; + if (left < 0x80000000L) + val = 0x80000000L - left; + write_pmc(event->hw.idx, val); perf_event_update_userpage(event); perf_pmu_enable(event->pmu); |