[tip:perf/pebs] perf, x86: Fixup the PEBS handler for Core2 cpus

tip-bot for Peter Zijlstra
2010-03-10T13:25:25Z

Commit-ID: d80c7502ff63aa0d99d8c0c5803d28bbef67a74e
Gitweb: http://git.kernel.org/tip/d80c7502ff63aa0d99d8c0c5803d28bbef67a74e
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Tue, 9 Mar 2010 11:41:02 +0100
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 10 Mar 2010 13:23:39 +0100

perf, x86: Fixup the PEBS handler for Core2 cpus

Pull the core handler in line with the nhm one, also make sure we always
drain the buffer.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/kernel/cpu/perf_event_intel_ds.c | 38 ++++++++++++++++++----------
1 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 2423694..1bfd59b 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -472,20 +472,39 @@ static void intel_pmu_drain_pebs_core(struct pt_regs *iregs)
struct pt_regs regs;
int n;

- if (!event || !ds || !x86_pmu.pebs)
+ if (!ds || !x86_pmu.pebs)
return;

at = (struct pebs_record_core *)(unsigned long)ds->pebs_buffer_base;
top = (struct pebs_record_core *)(unsigned long)ds->pebs_index;

- if (top <= at)
+ /*
+ * Whatever else happens, drain the thing
+ */
+ ds->pebs_index = ds->pebs_buffer_base;
+
+ if (!test_bit(0, cpuc->active_mask))
return;

- ds->pebs_index = ds->pebs_buffer_base;
+ WARN_ON_ONCE(!event);
+
+ if (!event->attr.precise)
+ return;
+
+ n = top - at;
+ if (n <= 0)
+ return;

if (!intel_pmu_save_and_restart(event))
return;

+ /*
+ * Should not happen, we program the threshold at 1 and do not
+ * set a reset value.
+ */
+ WARN_ON_ONCE(n > 1);
+ at += n - 1;
+
perf_sample_data_init(&data, 0);
data.period = event->hw.last_period;

@@ -495,14 +514,6 @@ static void intel_pmu_drain_pebs_core(struct pt_regs *iregs)
data.raw = &raw;
}

- n = top - at;
-
- /*
- * Should not happen, we program the threshold at 1 and do not
- * set a reset value.
- */
- WARN_ON_ONCE(n > 1);
-
/*
* We use the interrupt regs as a base because the PEBS record
* does not contain a full regs set, specifically it seems to
@@ -545,12 +556,11 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
at = (struct pebs_record_nhm *)(unsigned long)ds->pebs_buffer_base;
top = (struct pebs_record_nhm *)(unsigned long)ds->pebs_index;

- if (top <= at)
- return;
-
ds->pebs_index = ds->pebs_buffer_base;

n = top - at;
+ if (n <= 0)
+ return;

/*
* Should not happen, we program the threshold at 1 and do not