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

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Message-ID: <1333390758-10893-2-git-send-email-robert.richter@amd.com>
Date:	Mon, 2 Apr 2012 20:19:07 +0200
From:	Robert Richter <robert.richter@....com>
To:	Ingo Molnar <mingo@...e.hu>
CC:	Peter Zijlstra <peterz@...radead.org>,
	Stephane Eranian <eranian@...gle.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Robert Richter <robert.richter@....com>
Subject: [PATCH 01/12] perf/x86-ibs: Fix update of period

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@....com>
---
 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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