[PATCH 01/12] perf/x86-ibs: Fix update of period

[Robert Richter]

The last sw period was not correctly updated on overflow and thus led
to wrong distribution of events. We always need to properly initialize
data.period in struct perf_sample_data.

Signed-off-by: Robert Richter <robert.richter@xxxxxxx>
---
 arch/x86/kernel/cpu/perf_event_amd_ibs.c |   27 ++++++++++++++-------------
 1 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
index 573d248..6eb6451 100644
--- a/arch/x86/kernel/cpu/perf_event_amd_ibs.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
@@ -386,7 +386,21 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 	if (!(*buf++ & perf_ibs->valid_mask))
 		return 0;
 
+	/*
+	 * Emulate IbsOpCurCnt in MSRC001_1033 (IbsOpCtl), not
+	 * supported in all cpus. As this triggered an interrupt, we
+	 * set the current count to the max count.
+	 */
+	config = ibs_data.regs[0];
+	if (perf_ibs == &perf_ibs_op && !(ibs_caps & IBS_CAPS_RDWROPCNT)) {
+		config &= ~IBS_OP_CUR_CNT;
+		config |= (config & IBS_OP_MAX_CNT) << 36;
+	}
+
+	perf_ibs_event_update(perf_ibs, event, config);
 	perf_sample_data_init(&data, 0);
+	data.period = event->hw.last_period;
+
 	if (event->attr.sample_type & PERF_SAMPLE_RAW) {
 		ibs_data.caps = ibs_caps;
 		size = 1;
@@ -405,19 +419,6 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 
 	regs = *iregs; /* XXX: update ip from ibs sample */
 
-	/*
-	 * Emulate IbsOpCurCnt in MSRC001_1033 (IbsOpCtl), not
-	 * supported in all cpus. As this triggered an interrupt, we
-	 * set the current count to the max count.
-	 */
-	config = ibs_data.regs[0];
-	if (perf_ibs == &perf_ibs_op && !(ibs_caps & IBS_CAPS_RDWROPCNT)) {
-		config &= ~IBS_OP_CUR_CNT;
-		config |= (config & IBS_OP_MAX_CNT) << 36;
-	}
-
-	perf_ibs_event_update(perf_ibs, event, config);
-
 	overflow = perf_ibs_set_period(perf_ibs, hwc, &config);
 	reenable = !(overflow && perf_event_overflow(event, &data, &regs));
 	config = (config >> 4) | (reenable ? perf_ibs->enable_mask : 0);
-- 
1.7.8.4


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