[V2,4/5] perf mem: Clean up perf_mem_event__supported()

Commit Message

Liang, Kan Dec. 7, 2023, 7:23 p.m. UTC

From: Kan Liang <[e-mail]>

For some ARCHs, e.g., ARM and AMD, to get the availability of the
mem-events, perf checks the existence of a specific PMU. For the other
ARCHs, e.g., Intel and Power, perf has to check the existence of some
specific events.

The current perf only iterates the mem-events-supported PMUs. It's not
required to check the existence of a specific PMU anymore.

Rename sysfs_name to event_name, which stores the specific mem-events.
Perf only needs to check those events for the availability of the
mem-events.

Rename perf_mem_event__supported to perf_pmu__mem_events_supported.

Reviewed-by: Ian Rogers <[e-mail]>
Tested-by: Ravi Bangoria <[e-mail]>
Signed-off-by: Kan Liang <[e-mail]>
---
 tools/perf/arch/arm64/util/mem-events.c   |  8 ++++----
 tools/perf/arch/powerpc/util/mem-events.c |  8 ++++----
 tools/perf/arch/x86/util/mem-events.c     | 20 ++++++++++----------
 tools/perf/util/mem-events.c              | 22 ++++++++++++----------
 tools/perf/util/mem-events.h              |  2 +-
 5 files changed, 31 insertions(+), 29 deletions(-)

Comments

Leo Yan Dec. 9, 2023, 6:17 a.m. UTC | #1

On Thu, Dec 07, 2023 at 11:23:37AM -0800, [e-mail] wrote:
> From: Kan Liang <[e-mail]>
> 
> For some ARCHs, e.g., ARM and AMD, to get the availability of the
> mem-events, perf checks the existence of a specific PMU. For the other
> ARCHs, e.g., Intel and Power, perf has to check the existence of some
> specific events.
> 
> The current perf only iterates the mem-events-supported PMUs. It's not
> required to check the existence of a specific PMU anymore.

With this change, both Arm and AMD archs have no chance to detect if the
hardware (or the device driver) is supported and the tool will always
take the memory events are exited on the system, right?

Thanks,
Leo

Liang, Kan Dec. 11, 2023, 6:44 p.m. UTC | #2

On 2023-12-09 1:17 a.m., Leo Yan wrote:
> On Thu, Dec 07, 2023 at 11:23:37AM -0800, [e-mail] wrote:
>> From: Kan Liang <[e-mail]>
>>
>> For some ARCHs, e.g., ARM and AMD, to get the availability of the
>> mem-events, perf checks the existence of a specific PMU. For the other
>> ARCHs, e.g., Intel and Power, perf has to check the existence of some
>> specific events.
>>
>> The current perf only iterates the mem-events-supported PMUs. It's not
>> required to check the existence of a specific PMU anymore.
> 
> With this change, both Arm and AMD archs have no chance to detect if the
> hardware (or the device driver) is supported and the tool will always
> take the memory events are exited on the system, right?

Currently, the Arm and AMD only check the specific PMU. If the PMU is
detected, the memory events are supported. The patch set doesn't change
it. It just moves the check to perf_pmu__arch_init(). When the specific
PMU is initialized, the mem_events is assigned. You don't need to do
runtime sysfs check. It should be an improvement for ARM and AMD.

Thanks,
Kan

> 
> Thanks,
> Leo
>

Leo Yan Dec. 13, 2023, 1:51 p.m. UTC | #3

On Mon, Dec 11, 2023 at 01:44:54PM -0500, Liang, Kan wrote:
> 
> 
> On 2023-12-09 1:17 a.m., Leo Yan wrote:
> > On Thu, Dec 07, 2023 at 11:23:37AM -0800, [e-mail] wrote:
> >> From: Kan Liang <[e-mail]>
> >>
> >> For some ARCHs, e.g., ARM and AMD, to get the availability of the
> >> mem-events, perf checks the existence of a specific PMU. For the other
> >> ARCHs, e.g., Intel and Power, perf has to check the existence of some
> >> specific events.
> >>
> >> The current perf only iterates the mem-events-supported PMUs. It's not
> >> required to check the existence of a specific PMU anymore.
> > 
> > With this change, both Arm and AMD archs have no chance to detect if the
> > hardware (or the device driver) is supported and the tool will always
> > take the memory events are exited on the system, right?
> 
> Currently, the Arm and AMD only check the specific PMU. If the PMU is
> detected, the memory events are supported. The patch set doesn't change
> it. It just moves the check to perf_pmu__arch_init(). When the specific
> PMU is initialized, the mem_events is assigned. You don't need to do
> runtime sysfs check. It should be an improvement for ARM and AMD.

Okay, I understand now.  For Arm SPE, it has a dedicated PMU so if the
PMU is detected, then we can assume the memory events are supported.

For other cases, you need to check furthermore if PMU has supported
specific memory events.

This patch is fine for me, you could ignore my comment for the
regression caused by this patch.

Thanks,
Leo

Ravi Bangoria Dec. 13, 2023, 1:55 p.m. UTC | #4

>>>> For some ARCHs, e.g., ARM and AMD, to get the availability of the
>>>> mem-events, perf checks the existence of a specific PMU. For the other
>>>> ARCHs, e.g., Intel and Power, perf has to check the existence of some
>>>> specific events.
>>>>
>>>> The current perf only iterates the mem-events-supported PMUs. It's not
>>>> required to check the existence of a specific PMU anymore.
>>>
>>> With this change, both Arm and AMD archs have no chance to detect if the
>>> hardware (or the device driver) is supported and the tool will always
>>> take the memory events are exited on the system, right?
>>
>> Currently, the Arm and AMD only check the specific PMU. If the PMU is
>> detected, the memory events are supported. The patch set doesn't change
>> it. It just moves the check to perf_pmu__arch_init(). When the specific
>> PMU is initialized, the mem_events is assigned. You don't need to do
>> runtime sysfs check. It should be an improvement for ARM and AMD.
> 
> Okay, I understand now.  For Arm SPE, it has a dedicated PMU so if the
> PMU is detected, then we can assume the memory events are supported.

Same for AMD. If ibs_op// pmu is present, the mem event is supported.

Thanks,
Ravi

Patch

diff --git a/tools/perf/arch/arm64/util/mem-events.c b/tools/perf/arch/arm64/util/mem-events.c
index eb2ef84f0fc8..590dddd6b0ab 100644
--- a/tools/perf/arch/arm64/util/mem-events.c
+++ b/tools/perf/arch/arm64/util/mem-events.c
@@ -2,10 +2,10 @@ 
 #include "map_symbol.h"
 #include "mem-events.h"
 
-#define E(t, n, s, l, a) { .tag = t, .name = n, .sysfs_name = s, .ldlat = l, .aux_event = a }
+#define E(t, n, s, l, a) { .tag = t, .name = n, .event_name = s, .ldlat = l, .aux_event = a }
 
 struct perf_mem_event perf_mem_events_arm[PERF_MEM_EVENTS__MAX] = {
-	E("spe-load",	"%s/ts_enable=1,pa_enable=1,load_filter=1,store_filter=0,min_latency=%u/",	"arm_spe_0",	true,	0),
-	E("spe-store",	"%s/ts_enable=1,pa_enable=1,load_filter=0,store_filter=1/",			"arm_spe_0",	false,	0),
-	E("spe-ldst",	"%s/ts_enable=1,pa_enable=1,load_filter=1,store_filter=1,min_latency=%u/",	"arm_spe_0",	true,	0),
+	E("spe-load",	"%s/ts_enable=1,pa_enable=1,load_filter=1,store_filter=0,min_latency=%u/",	NULL,	true,	0),
+	E("spe-store",	"%s/ts_enable=1,pa_enable=1,load_filter=0,store_filter=1/",			NULL,	false,	0),
+	E("spe-ldst",	"%s/ts_enable=1,pa_enable=1,load_filter=1,store_filter=1,min_latency=%u/",	NULL,	true,	0),
 };
diff --git a/tools/perf/arch/powerpc/util/mem-events.c b/tools/perf/arch/powerpc/util/mem-events.c
index b7883e38950f..72a6ac2b52f5 100644
--- a/tools/perf/arch/powerpc/util/mem-events.c
+++ b/tools/perf/arch/powerpc/util/mem-events.c
@@ -2,10 +2,10 @@ 
 #include "map_symbol.h"
 #include "mem-events.h"
 
-#define E(t, n, s, l, a) { .tag = t, .name = n, .sysfs_name = s, .ldlat = l, .aux_event = a }
+#define E(t, n, s, l, a) { .tag = t, .name = n, .event_name = s, .ldlat = l, .aux_event = a }
 
 struct perf_mem_event perf_mem_events_power[PERF_MEM_EVENTS__MAX] = {
-	E("ldlat-loads",	"%s/mem-loads/",	"cpu/events/mem-loads",		false,	0),
-	E("ldlat-stores",	"%s/mem-stores/",	"cpu/events/mem-stores",	false,	0),
-	E(NULL,			NULL,			NULL,				false,	0),
+	E("ldlat-loads",	"%s/mem-loads/",	"mem-loads",	false,	0),
+	E("ldlat-stores",	"%s/mem-stores/",	"mem-stores",	false,	0),
+	E(NULL,			NULL,			NULL,		false,	0),
 };
diff --git a/tools/perf/arch/x86/util/mem-events.c b/tools/perf/arch/x86/util/mem-events.c
index f0e66a0151a0..b776d849fc64 100644
--- a/tools/perf/arch/x86/util/mem-events.c
+++ b/tools/perf/arch/x86/util/mem-events.c
@@ -9,24 +9,24 @@ 
 
 #define MEM_LOADS_AUX		0x8203
 
-#define E(t, n, s, l, a) { .tag = t, .name = n, .sysfs_name = s, .ldlat = l, .aux_event = a }
+#define E(t, n, s, l, a) { .tag = t, .name = n, .event_name = s, .ldlat = l, .aux_event = a }
 
 struct perf_mem_event perf_mem_events_intel[PERF_MEM_EVENTS__MAX] = {
-	E("ldlat-loads",	"%s/mem-loads,ldlat=%u/P",	"%s/events/mem-loads",	true,	0),
-	E("ldlat-stores",	"%s/mem-stores/P",		"%s/events/mem-stores",	false,	0),
-	E(NULL,			NULL,				NULL,			false,	0),
+	E("ldlat-loads",	"%s/mem-loads,ldlat=%u/P",	"mem-loads",	true,	0),
+	E("ldlat-stores",	"%s/mem-stores/P",		"mem-stores",	false,	0),
+	E(NULL,			NULL,				NULL,		false,	0),
 };
 
 struct perf_mem_event perf_mem_events_intel_aux[PERF_MEM_EVENTS__MAX] = {
-	E("ldlat-loads",	"{%s/mem-loads-aux/,%s/mem-loads,ldlat=%u/}:P",	"%s/events/mem-loads",	true,	MEM_LOADS_AUX),
-	E("ldlat-stores",	"%s/mem-stores/P",		"%s/events/mem-stores",	false,	0),
-	E(NULL,			NULL,				NULL,			false,	0),
+	E("ldlat-loads",	"{%s/mem-loads-aux/,%s/mem-loads,ldlat=%u/}:P",	"mem-loads",	true,	MEM_LOADS_AUX),
+	E("ldlat-stores",	"%s/mem-stores/P",		"mem-stores",	false,	0),
+	E(NULL,			NULL,				NULL,		false,	0),
 };
 
 struct perf_mem_event perf_mem_events_amd[PERF_MEM_EVENTS__MAX] = {
-	E(NULL,		NULL,		NULL,		false,	0),
-	E(NULL,		NULL,		NULL,		false,	0),
-	E("mem-ldst",	"%s//",		"ibs_op",	false,	0),
+	E(NULL,		NULL,		NULL,	false,	0),
+	E(NULL,		NULL,		NULL,	false,	0),
+	E("mem-ldst",	"%s//",		NULL,	false,	0),
 };
 
 bool is_mem_loads_aux_event(struct evsel *leader)
diff --git a/tools/perf/util/mem-events.c b/tools/perf/util/mem-events.c
index c9a40b64e538..0d174f161034 100644
--- a/tools/perf/util/mem-events.c
+++ b/tools/perf/util/mem-events.c
@@ -17,12 +17,12 @@ 
 
 unsigned int perf_mem_events__loads_ldlat = 30;
 
-#define E(t, n, s, l, a) { .tag = t, .name = n, .sysfs_name = s, .ldlat = l, .aux_event = a }
+#define E(t, n, s, l, a) { .tag = t, .name = n, .event_name = s, .ldlat = l, .aux_event = a }
 
 struct perf_mem_event perf_mem_events[PERF_MEM_EVENTS__MAX] = {
-	E("ldlat-loads",	"%s/mem-loads,ldlat=%u/P",	"cpu/events/mem-loads",		true,	0),
-	E("ldlat-stores",	"%s/mem-stores/P",		"cpu/events/mem-stores",	false,	0),
-	E(NULL,			NULL,				NULL,				false,	0),
+	E("ldlat-loads",	"%s/mem-loads,ldlat=%u/P",	"mem-loads",	true,	0),
+	E("ldlat-stores",	"%s/mem-stores/P",		"mem-stores",	false,	0),
+	E(NULL,			NULL,				NULL,		false,	0),
 };
 #undef E
 
@@ -147,15 +147,17 @@  int perf_pmu__mem_events_parse(struct perf_pmu *pmu, const char *str)
 	return -1;
 }
 
-static bool perf_mem_event__supported(const char *mnt, struct perf_pmu *pmu,
+static bool perf_pmu__mem_events_supported(const char *mnt, struct perf_pmu *pmu,
 				      struct perf_mem_event *e)
 {
-	char sysfs_name[100];
 	char path[PATH_MAX];
 	struct stat st;
 
-	scnprintf(sysfs_name, sizeof(sysfs_name), e->sysfs_name, pmu->name);
-	scnprintf(path, PATH_MAX, "%s/devices/%s", mnt, sysfs_name);
+	if (!e->event_name)
+		return true;
+
+	scnprintf(path, PATH_MAX, "%s/devices/%s/events/%s", mnt, pmu->name, e->event_name);
+
 	return !stat(path, &st);
 }
 
@@ -178,7 +180,7 @@  int perf_pmu__mem_events_init(struct perf_pmu *pmu)
 		if (!e->tag)
 			continue;
 
-		e->supported |= perf_mem_event__supported(mnt, pmu, e);
+		e->supported |= perf_pmu__mem_events_supported(mnt, pmu, e);
 		if (e->supported)
 			found = true;
 	}
@@ -230,7 +232,7 @@  int perf_mem_events__record_args(const char **rec_argv, int *argv_nr,
 			} else {
 				const char *s = perf_pmu__mem_events_name(j, pmu);
 
-				if (!perf_mem_event__supported(mnt, pmu, e))
+				if (!perf_pmu__mem_events_supported(mnt, pmu, e))
 					continue;
 
 				rec_argv[i++] = "-e";
diff --git a/tools/perf/util/mem-events.h b/tools/perf/util/mem-events.h
index 79d342768d12..f817a507b106 100644
--- a/tools/perf/util/mem-events.h
+++ b/tools/perf/util/mem-events.h
@@ -18,7 +18,7 @@  struct perf_mem_event {
 	u32		aux_event;
 	const char	*tag;
 	const char	*name;
-	const char	*sysfs_name;
+	const char	*event_name;
 };
 
 struct mem_info {