From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, will.deacon@arm.com,
mark.rutland@arm.com, robin.murphy@arm.com,
Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH v2 3/5] arm_pmu: Add support for 64bit event counters
Date: Tue, 29 May 2018 11:55:54 +0100 [thread overview]
Message-ID: <1527591356-10934-4-git-send-email-suzuki.poulose@arm.com> (raw)
In-Reply-To: <1527591356-10934-1-git-send-email-suzuki.poulose@arm.com>
Each PMU has a set of 32bit event counters. But in some
special cases, the events could be counted using counters
which are effectively 64bit wide.
e.g, Arm V8 PMUv3 has a 64 bit cycle counter which can count
only the CPU cycles. Also, the PMU can chain the event counters
to effectively count as a 64bit counter.
Add support for tracking the events that uses 64bit counters.
This only affects the periods set for each counter in the core
driver.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
Changes since v1:
- Rename ARMPMU_EVT_LONG => ARMPMU_EVT_64BIT
---
drivers/perf/arm_pmu.c | 14 ++++++++------
include/linux/perf/arm_pmu.h | 6 ++++++
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 8962d26..ff858e6 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -28,9 +28,10 @@
static DEFINE_PER_CPU(struct arm_pmu *, cpu_armpmu);
static DEFINE_PER_CPU(int, cpu_irq);
-static inline u64 arm_pmu_max_period(void)
+static inline u64 arm_pmu_event_max_period(struct perf_event *event)
{
- return (1ULL << 32) - 1;
+ return (event->hw.flags & ARMPMU_EVT_64BIT) ?
+ ~0ULL : (1ULL << 32) - 1;
}
static int
@@ -122,7 +123,7 @@ int armpmu_event_set_period(struct perf_event *event)
u64 max_period;
int ret = 0;
- max_period = arm_pmu_max_period();
+ max_period = arm_pmu_event_max_period(event);
if (unlikely(left <= -period)) {
left = period;
local64_set(&hwc->period_left, left);
@@ -148,7 +149,7 @@ int armpmu_event_set_period(struct perf_event *event)
local64_set(&hwc->prev_count, (u64)-left);
- armpmu->write_counter(event, (u64)(-left) & 0xffffffff);
+ armpmu->write_counter(event, (u64)(-left) & max_period);
perf_event_update_userpage(event);
@@ -160,7 +161,7 @@ u64 armpmu_event_update(struct perf_event *event)
struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
struct hw_perf_event *hwc = &event->hw;
u64 delta, prev_raw_count, new_raw_count;
- u64 max_period = arm_pmu_max_period();
+ u64 max_period = arm_pmu_event_max_period(event);
again:
prev_raw_count = local64_read(&hwc->prev_count);
@@ -368,6 +369,7 @@ __hw_perf_event_init(struct perf_event *event)
struct hw_perf_event *hwc = &event->hw;
int mapping;
+ hwc->flags = 0;
mapping = armpmu->map_event(event);
if (mapping < 0) {
@@ -410,7 +412,7 @@ __hw_perf_event_init(struct perf_event *event)
* is far less likely to overtake the previous one unless
* you have some serious IRQ latency issues.
*/
- hwc->sample_period = arm_pmu_max_period() >> 1;
+ hwc->sample_period = arm_pmu_event_max_period(event) >> 1;
hwc->last_period = hwc->sample_period;
local64_set(&hwc->period_left, hwc->sample_period);
}
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index f1cfe12..1e26b14 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -25,6 +25,12 @@
*/
#define ARMPMU_MAX_HWEVENTS 32
+/*
+ * ARM PMU hw_event flags
+ */
+/* Event uses a 64bit counter */
+#define ARMPMU_EVT_64BIT 1
+
#define HW_OP_UNSUPPORTED 0xFFFF
#define C(_x) PERF_COUNT_HW_CACHE_##_x
#define CACHE_OP_UNSUPPORTED 0xFFFF
--
2.7.4
next prev parent reply other threads:[~2018-05-29 10:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-29 10:55 [PATCH v2 0/5] arm64: perf: Support for chained counters Suzuki K Poulose
2018-05-29 10:55 ` [PATCH v2 1/5] arm_pmu: Clean up maximum period handling Suzuki K Poulose
2018-05-29 10:55 ` [PATCH v2 2/5] arm_pmu: Change API to support 64bit counter values Suzuki K Poulose
2018-05-29 10:55 ` Suzuki K Poulose [this message]
2018-06-06 16:48 ` [PATCH v2 3/5] arm_pmu: Add support for 64bit event counters Mark Rutland
2018-06-07 7:34 ` Suzuki K Poulose
2018-05-29 10:55 ` [PATCH v2 4/5] arm_pmu: Tidy up clear_event_idx call backs Suzuki K Poulose
2018-05-29 10:55 ` [PATCH v2 5/5] arm64: perf: Add support for chaining event counters Suzuki K Poulose
2018-06-06 18:01 ` Mark Rutland
2018-06-08 14:46 ` Suzuki K Poulose
2018-06-08 15:24 ` Mark Rutland
2018-06-08 16:05 ` Suzuki K Poulose
2018-06-11 13:54 ` Suzuki K Poulose
2018-06-11 14:24 ` Mark Rutland
2018-06-11 16:18 ` Suzuki K Poulose
2018-06-05 15:00 ` [PATCH v2 0/5] arm64: perf: Support for chained counters Julien Thierry
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1527591356-10934-4-git-send-email-suzuki.poulose@arm.com \
--to=suzuki.poulose@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=robin.murphy@arm.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).