* [PATCH v6 10/11] drivers: perf: hisi: use poll method when no IRQ for MN counter overflow
@ 2017-03-10 6:29 Anurup M
2017-03-21 17:17 ` Mark Rutland
0 siblings, 1 reply; 3+ messages in thread
From: Anurup M @ 2017-03-10 6:29 UTC (permalink / raw)
To: mark.rutland, will.deacon
Cc: linux-kernel, linux-arm-kernel, anurup.m, zhangshaokun,
tanxiaojun, xuwei5, sanil.kumar, john.garry, gabriele.paoloni,
shiju.jose, huangdaode, linuxarm, dikshit.n, shyju.pv,
anurupvasu
When no IRQ is supported in hardware, use hrtimer to poll and
update event counter and avoid overflow condition for MN PMU.
An interval of 8 seconds is used for the hrtimer.
Signed-off-by: Anurup M <anurup.m@huawei.com>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Dikshit N <dikshit.n@huawei.com>
---
drivers/perf/hisilicon/hisi_uncore_mn.c | 39 +++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/perf/hisilicon/hisi_uncore_mn.c b/drivers/perf/hisilicon/hisi_uncore_mn.c
index 18316dc..55b6165 100644
--- a/drivers/perf/hisilicon/hisi_uncore_mn.c
+++ b/drivers/perf/hisilicon/hisi_uncore_mn.c
@@ -20,6 +20,8 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/bitmap.h>
+#include <linux/hrtimer.h>
+#include <linux/ktime.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
@@ -56,6 +58,15 @@ enum armv8_hisi_mn_counters {
#define GET_MODULE_ID(hwmod_data) hwmod_data->mn_hwcfg.module_id
+/*
+ * Default timer frequency to poll and avoid counter overflow.
+ * CPU speed = 2.4Ghz and number of CPU cores in a SCCL is 16.
+ * For a single MN event on a CPU core consumes 200 cycles.
+ * So overflow time = (2^31 * 200) / (16 * 2.4G) which is about 21 seconds
+ * So on a safe side we use a timer interval of 8sec
+ */
+#define MN1_HRTIMER_INTERVAL (8LL * MSEC_PER_SEC)
+
struct hisi_mn_hwcfg {
u32 module_id;
};
@@ -272,6 +283,15 @@ static const struct of_device_id mn_of_match[] = {
};
MODULE_DEVICE_TABLE(of, mn_of_match);
+/* Use hrtimer when no IRQ, to poll for avoiding counter overflow */
+static void hisi_mn_hrtimer_init(struct hisi_pmu *mn_pmu)
+{
+ INIT_LIST_HEAD(&mn_pmu->active_list);
+ mn_pmu->ops->start_hrtimer = hisi_hrtimer_start;
+ mn_pmu->ops->stop_hrtimer = hisi_hrtimer_stop;
+ hisi_hrtimer_init(mn_pmu, MN1_HRTIMER_INTERVAL);
+}
+
static int hisi_mn_init_data(struct hisi_pmu *mn_pmu,
struct hisi_djtag_client *client)
{
@@ -314,6 +334,12 @@ static int hisi_mn_init_data(struct hisi_pmu *mn_pmu,
} else
return -EINVAL;
+ /*
+ * Use poll method to avoid counter overflow as
+ * overflow IRQ is not supported in hardware.
+ */
+ hisi_mn_hrtimer_init(mn_pmu);
+
return 0;
}
@@ -361,11 +387,24 @@ static const struct attribute_group hisi_mn_cpumask_attr_group = {
.attrs = hisi_mn_cpumask_attrs,
};
+static DEVICE_ATTR(hrtimer_interval, 0444, hisi_hrtimer_interval_sysfs_show,
+ NULL);
+
+static struct attribute *hisi_mn_hrtimer_interval_attrs[] = {
+ &dev_attr_hrtimer_interval.attr,
+ NULL,
+};
+
+static const struct attribute_group hisi_mn_hrtimer_interval_attr_group = {
+ .attrs = hisi_mn_hrtimer_interval_attrs,
+};
+
static const struct attribute_group *hisi_mn_pmu_attr_groups[] = {
&hisi_mn_attr_group,
&hisi_mn_format_group,
&hisi_mn_events_group,
&hisi_mn_cpumask_attr_group,
+ &hisi_mn_hrtimer_interval_attr_group,
NULL,
};
--
2.1.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v6 10/11] drivers: perf: hisi: use poll method when no IRQ for MN counter overflow
2017-03-10 6:29 [PATCH v6 10/11] drivers: perf: hisi: use poll method when no IRQ for MN counter overflow Anurup M
@ 2017-03-21 17:17 ` Mark Rutland
2017-03-24 6:43 ` Anurup M
0 siblings, 1 reply; 3+ messages in thread
From: Mark Rutland @ 2017-03-21 17:17 UTC (permalink / raw)
To: Anurup M
Cc: will.deacon, linux-kernel, linux-arm-kernel, anurup.m,
zhangshaokun, tanxiaojun, xuwei5, sanil.kumar, john.garry,
gabriele.paoloni, shiju.jose, huangdaode, linuxarm, dikshit.n,
shyju.pv
On Fri, Mar 10, 2017 at 01:29:01AM -0500, Anurup M wrote:
> When no IRQ is supported in hardware, use hrtimer to poll and
> update event counter and avoid overflow condition for MN PMU.
> An interval of 8 seconds is used for the hrtimer.
Please fold this into the main MN patch.
The comments on the L3 hrtimer patch also apply here.
Thanks,
Mark.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v6 10/11] drivers: perf: hisi: use poll method when no IRQ for MN counter overflow
2017-03-21 17:17 ` Mark Rutland
@ 2017-03-24 6:43 ` Anurup M
0 siblings, 0 replies; 3+ messages in thread
From: Anurup M @ 2017-03-24 6:43 UTC (permalink / raw)
To: Mark Rutland
Cc: will.deacon, linux-kernel, linux-arm-kernel, anurup.m,
zhangshaokun, tanxiaojun, xuwei5, sanil.kumar, john.garry,
gabriele.paoloni, shiju.jose, huangdaode, linuxarm, dikshit.n,
shyju.pv
On Tuesday 21 March 2017 10:47 PM, Mark Rutland wrote:
> On Fri, Mar 10, 2017 at 01:29:01AM -0500, Anurup M wrote:
>> When no IRQ is supported in hardware, use hrtimer to poll and
>> update event counter and avoid overflow condition for MN PMU.
>> An interval of 8 seconds is used for the hrtimer.
> Please fold this into the main MN patch.
>
> The comments on the L3 hrtimer patch also apply here.
Sure. shall fix these comments. and fold to main MN patch.
Thanks,
Anurup
> Thanks,
> Mark.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-03-10 6:29 [PATCH v6 10/11] drivers: perf: hisi: use poll method when no IRQ for MN counter overflow Anurup M
2017-03-21 17:17 ` Mark Rutland
2017-03-24 6:43 ` Anurup M
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