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From: Stephen Boyd <sboyd@codeaurora.org>
To: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 4/7] ARM: perf_event: Add hook for event index clearing
Date: Fri,  7 Feb 2014 13:01:22 -0800	[thread overview]
Message-ID: <1391806885-24210-5-git-send-email-sboyd@codeaurora.org> (raw)
In-Reply-To: <1391806885-24210-1-git-send-email-sboyd@codeaurora.org>

On Krait processors we have a many-to-one relationship between
raw CPU events and the event programmed into the PMNx counter.
Two raw CPU events could map to the same value programmed in the
PMNx counter. To avoid this problem, we check for collisions
during the get_event_idx() callback by setting a bit in a bitmap
whenever a certain event is used in a PMNx counter (see the next
patch). Unfortunately, we don't have a hook to clear this bit in
the bitmap when the event is deleted so let's add an optional
clear_event_idx() callback for this purpose.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 arch/arm/include/asm/pmu.h   | 2 ++
 arch/arm/kernel/perf_event.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/arm/include/asm/pmu.h b/arch/arm/include/asm/pmu.h
index f24edad26c70..ae1919be8f98 100644
--- a/arch/arm/include/asm/pmu.h
+++ b/arch/arm/include/asm/pmu.h
@@ -71,6 +71,8 @@ struct arm_pmu {
 	void		(*disable)(struct perf_event *event);
 	int		(*get_event_idx)(struct pmu_hw_events *hw_events,
 					 struct perf_event *event);
+	void		(*clear_event_idx)(struct pmu_hw_events *hw_events,
+					 struct perf_event *event);
 	int		(*set_event_filter)(struct hw_perf_event *evt,
 					    struct perf_event_attr *attr);
 	u32		(*read_counter)(struct perf_event *event);
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index b0c8489018d3..361a1aaee7c8 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -207,6 +207,8 @@ armpmu_del(struct perf_event *event, int flags)
 	armpmu_stop(event, PERF_EF_UPDATE);
 	hw_events->events[idx] = NULL;
 	clear_bit(idx, hw_events->used_mask);
+	if (armpmu->clear_event_idx)
+		armpmu->clear_event_idx(hw_events, event);
 
 	perf_event_update_userpage(event);
 }
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

WARNING: multiple messages have this Message-ID
From: sboyd@codeaurora.org (Stephen Boyd)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 4/7] ARM: perf_event: Add hook for event index clearing
Date: Fri,  7 Feb 2014 13:01:22 -0800	[thread overview]
Message-ID: <1391806885-24210-5-git-send-email-sboyd@codeaurora.org> (raw)
In-Reply-To: <1391806885-24210-1-git-send-email-sboyd@codeaurora.org>

On Krait processors we have a many-to-one relationship between
raw CPU events and the event programmed into the PMNx counter.
Two raw CPU events could map to the same value programmed in the
PMNx counter. To avoid this problem, we check for collisions
during the get_event_idx() callback by setting a bit in a bitmap
whenever a certain event is used in a PMNx counter (see the next
patch). Unfortunately, we don't have a hook to clear this bit in
the bitmap when the event is deleted so let's add an optional
clear_event_idx() callback for this purpose.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 arch/arm/include/asm/pmu.h   | 2 ++
 arch/arm/kernel/perf_event.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/arm/include/asm/pmu.h b/arch/arm/include/asm/pmu.h
index f24edad26c70..ae1919be8f98 100644
--- a/arch/arm/include/asm/pmu.h
+++ b/arch/arm/include/asm/pmu.h
@@ -71,6 +71,8 @@ struct arm_pmu {
 	void		(*disable)(struct perf_event *event);
 	int		(*get_event_idx)(struct pmu_hw_events *hw_events,
 					 struct perf_event *event);
+	void		(*clear_event_idx)(struct pmu_hw_events *hw_events,
+					 struct perf_event *event);
 	int		(*set_event_filter)(struct hw_perf_event *evt,
 					    struct perf_event_attr *attr);
 	u32		(*read_counter)(struct perf_event *event);
diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index b0c8489018d3..361a1aaee7c8 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -207,6 +207,8 @@ armpmu_del(struct perf_event *event, int flags)
 	armpmu_stop(event, PERF_EF_UPDATE);
 	hw_events->events[idx] = NULL;
 	clear_bit(idx, hw_events->used_mask);
+	if (armpmu->clear_event_idx)
+		armpmu->clear_event_idx(hw_events, event);
 
 	perf_event_update_userpage(event);
 }
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

  parent reply	other threads:[~2014-02-07 21:01 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-07 21:01 [PATCH v3 0/7] Support Krait CPU PMUs Stephen Boyd
2014-02-07 21:01 ` Stephen Boyd
2014-02-07 21:01 ` [PATCH v3 1/7] ARM: perf_event: Support percpu irqs for the CPU PMU Stephen Boyd
2014-02-07 21:01   ` Stephen Boyd
2014-02-07 21:01 ` [PATCH v3 2/7] ARM: perf_event: Assign pdev pointer earlier for CPU PMUs Stephen Boyd
2014-02-07 21:01   ` Stephen Boyd
2014-02-07 21:01 ` [PATCH v3 3/7] ARM: perf_event: Add basic support for Krait " Stephen Boyd
2014-02-07 21:01   ` Stephen Boyd
2014-02-07 21:01 ` Stephen Boyd [this message]
2014-02-07 21:01   ` [PATCH v3 4/7] ARM: perf_event: Add hook for event index clearing Stephen Boyd
2014-02-07 21:01 ` [PATCH v3 5/7] ARM: perf_event: Fully support Krait CPU PMU events Stephen Boyd
2014-02-07 21:01   ` Stephen Boyd
2014-02-07 21:01 ` [PATCH v3 6/7] devicetree: bindings: Document Krait performance monitor units (PMU) Stephen Boyd
2014-02-07 21:01   ` Stephen Boyd
2014-02-07 21:01   ` Stephen Boyd
2014-02-07 21:01 ` [PATCH v3 7/7] ARM: dts: msm: Add krait-pmu to platforms with Krait CPUs Stephen Boyd
2014-02-07 21:01   ` Stephen Boyd

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