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Message-ID: <20241218121437.1717-7-ravi.bangoria@amd.com>
Date: Wed, 18 Dec 2024 12:14:37 +0000
From: Ravi Bangoria <ravi.bangoria@....com>
To: <peterz@...radead.org>, <mingo@...hat.com>, <namhyung@...nel.org>
CC: <ravi.bangoria@....com>, <acme@...nel.org>, <eranian@...gle.com>,
<jolsa@...nel.org>, <irogers@...gle.com>, <kan.liang@...ux.intel.com>,
<bp@...en8.de>, <x86@...nel.org>, <linux-perf-users@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <santosh.shukla@....com>,
<ananth.narayan@....com>, <sandipan.das@....com>
Subject: [PATCH v2 6/6] perf mem/c2c amd: Add ldlat support
Perf mem and c2c uses IBS Op PMU on AMD platforms. IBS Op PMU on Zen5
uarch has added support for Load Latency filtering. Implement perf mem/
c2c --ldlat using IBS Op Load Latency filtering capability.
Some subtle differences between AMD and other arch:
o --ldlat is disabled by default on AMD
o Supported values are 128 to 2048.
Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>
---
tools/perf/Documentation/perf-c2c.txt | 10 ++++++--
tools/perf/Documentation/perf-mem.txt | 12 +++++++--
tools/perf/arch/x86/util/mem-events.c | 6 +++++
tools/perf/arch/x86/util/mem-events.h | 1 +
tools/perf/arch/x86/util/pmu.c | 20 ++++++++++++---
tools/perf/tests/shell/test_data_symbol.sh | 29 +++++++++++++++++++---
tools/perf/util/pmu.c | 11 ++++++++
tools/perf/util/pmu.h | 2 ++
8 files changed, 81 insertions(+), 10 deletions(-)
diff --git a/tools/perf/Documentation/perf-c2c.txt b/tools/perf/Documentation/perf-c2c.txt
index 856f0dfb8e5a..3e2f690f127a 100644
--- a/tools/perf/Documentation/perf-c2c.txt
+++ b/tools/perf/Documentation/perf-c2c.txt
@@ -54,8 +54,14 @@ RECORD OPTIONS
-l::
--ldlat::
- Configure mem-loads latency. Supported on Intel and Arm64 processors
- only. Ignored on other archs.
+ Configure mem-loads latency. Supported on Intel, Arm64 and some variants
+ of AMD platforms. Ignored on other archs.
+
+ On AMD platforms:
+ - Supported latency values are 128 to 2048 (both inclusive).
+ - Latency value which is a multiple of 128 incurs a little less profiling
+ overhead compared to other values.
+ - Load latency filtering is disabled by default.
-k::
--all-kernel::
diff --git a/tools/perf/Documentation/perf-mem.txt b/tools/perf/Documentation/perf-mem.txt
index 8a1bd9ff0f86..f28837d6b783 100644
--- a/tools/perf/Documentation/perf-mem.txt
+++ b/tools/perf/Documentation/perf-mem.txt
@@ -28,6 +28,8 @@ and kernel support is required. See linkperf:perf-arm-spe[1] for a setup guide.
Due to the statistical nature of SPE sampling, not every memory operation will
be sampled.
+On AMD this use IBS Op PMU to sample load-store operations.
+
COMMON OPTIONS
--------------
-f::
@@ -67,8 +69,14 @@ RECORD OPTIONS
Configure all used events to run in user space.
--ldlat <n>::
- Specify desired latency for loads event. Supported on Intel and Arm64
- processors only. Ignored on other archs.
+ Specify desired latency for loads event. Supported on Intel, Arm64 and
+ some variants of AMD platforms. Ignored on other archs.
+
+ On AMD platforms:
+ - Supported latency values are 128 to 2048 (both inclusive).
+ - Latency value which is a multiple of 128 incurs a little less profiling
+ overhead compared to other values.
+ - Load latency filtering is disabled by default.
REPORT OPTIONS
--------------
diff --git a/tools/perf/arch/x86/util/mem-events.c b/tools/perf/arch/x86/util/mem-events.c
index 62df03e91c7e..b38f519020ff 100644
--- a/tools/perf/arch/x86/util/mem-events.c
+++ b/tools/perf/arch/x86/util/mem-events.c
@@ -26,3 +26,9 @@ struct perf_mem_event perf_mem_events_amd[PERF_MEM_EVENTS__MAX] = {
E(NULL, NULL, NULL, false, 0),
E("mem-ldst", "%s//", NULL, false, 0),
};
+
+struct perf_mem_event perf_mem_events_amd_ldlat[PERF_MEM_EVENTS__MAX] = {
+ E(NULL, NULL, NULL, false, 0),
+ E(NULL, NULL, NULL, false, 0),
+ E("mem-ldst", "%s/ldlat=%u/", NULL, true, 0),
+};
diff --git a/tools/perf/arch/x86/util/mem-events.h b/tools/perf/arch/x86/util/mem-events.h
index f55c8d3b7d59..11e09a256f5b 100644
--- a/tools/perf/arch/x86/util/mem-events.h
+++ b/tools/perf/arch/x86/util/mem-events.h
@@ -6,5 +6,6 @@ extern struct perf_mem_event perf_mem_events_intel[PERF_MEM_EVENTS__MAX];
extern struct perf_mem_event perf_mem_events_intel_aux[PERF_MEM_EVENTS__MAX];
extern struct perf_mem_event perf_mem_events_amd[PERF_MEM_EVENTS__MAX];
+extern struct perf_mem_event perf_mem_events_amd_ldlat[PERF_MEM_EVENTS__MAX];
#endif /* _X86_MEM_EVENTS_H */
diff --git a/tools/perf/arch/x86/util/pmu.c b/tools/perf/arch/x86/util/pmu.c
index e0060dac2a9f..8712cbbbc712 100644
--- a/tools/perf/arch/x86/util/pmu.c
+++ b/tools/perf/arch/x86/util/pmu.c
@@ -18,8 +18,10 @@
#include "mem-events.h"
#include "util/env.h"
-void perf_pmu__arch_init(struct perf_pmu *pmu __maybe_unused)
+void perf_pmu__arch_init(struct perf_pmu *pmu)
{
+ struct perf_pmu_caps *ldlat_cap;
+
#ifdef HAVE_AUXTRACE_SUPPORT
if (!strcmp(pmu->name, INTEL_PT_PMU_NAME)) {
pmu->auxtrace = true;
@@ -33,8 +35,20 @@ void perf_pmu__arch_init(struct perf_pmu *pmu __maybe_unused)
#endif
if (x86__is_amd_cpu()) {
- if (!strcmp(pmu->name, "ibs_op"))
- pmu->mem_events = perf_mem_events_amd;
+ if (strcmp(pmu->name, "ibs_op"))
+ return;
+
+ pmu->mem_events = perf_mem_events_amd;
+
+ if (!perf_pmu__caps_parse(pmu))
+ return;
+
+ ldlat_cap = perf_pmu__get_cap(pmu, "ldlat");
+ if (!ldlat_cap || strcmp(ldlat_cap->value, "1"))
+ return;
+
+ perf_mem_events__loads_ldlat = 0;
+ pmu->mem_events = perf_mem_events_amd_ldlat;
} else if (pmu->is_core) {
if (perf_pmu__have_event(pmu, "mem-loads-aux"))
pmu->mem_events = perf_mem_events_intel_aux;
diff --git a/tools/perf/tests/shell/test_data_symbol.sh b/tools/perf/tests/shell/test_data_symbol.sh
index c86da0235059..747f5dc9d679 100755
--- a/tools/perf/tests/shell/test_data_symbol.sh
+++ b/tools/perf/tests/shell/test_data_symbol.sh
@@ -55,11 +55,34 @@ trap cleanup_files exit term int
echo "Recording workload..."
-# perf mem/c2c internally uses IBS PMU on AMD CPU which doesn't support
-# user/kernel filtering and per-process monitoring, spin program on
-# specific CPU and test in per-CPU mode.
is_amd=$(grep -E -c 'vendor_id.*AuthenticAMD' /proc/cpuinfo)
if (($is_amd >= 1)); then
+ mem_events="$(perf mem record -v -e list 2>&1)"
+ if ! [[ "$mem_events" =~ ^mem\-ldst.*ibs_op/(.*)/.*available ]]; then
+ echo "ERROR: mem-ldst event is not matching"
+ exit 1
+ fi
+
+ # --ldlat on AMD:
+ # o Zen4 and earlier uarch does not support ldlat
+ # o Even on supported platforms, it's disabled (--ldlat=0) by default.
+ ldlat=${BASH_REMATCH[1]}
+ if [[ -n $ldlat ]]; then
+ if ! [[ "$ldlat" =~ ldlat=0 ]]; then
+ echo "ERROR: ldlat not initialized to 0?"
+ exit 1
+ fi
+
+ mem_events="$(perf mem record -v --ldlat=150 -e list 2>&1)"
+ if ! [[ "$mem_events" =~ ^mem-ldst.*ibs_op/ldlat=150/.*available ]]; then
+ echo "ERROR: --ldlat not honored?"
+ exit 1
+ fi
+ fi
+
+ # perf mem/c2c internally uses IBS PMU on AMD CPU which doesn't
+ # support user/kernel filtering and per-process monitoring on older
+ # kernels, spin program on specific CPU and test in per-CPU mode.
perf mem record -vvv -o ${PERF_DATA} -C 0 -- taskset -c 0 $TEST_PROGRAM 2>"${ERR_FILE}" &
else
perf mem record -vvv --all-user -o ${PERF_DATA} -- $TEST_PROGRAM 2>"${ERR_FILE}" &
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 08a9d0bd9301..e480fd4744dd 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -2103,6 +2103,17 @@ static void perf_pmu__del_caps(struct perf_pmu *pmu)
}
}
+struct perf_pmu_caps *perf_pmu__get_cap(struct perf_pmu *pmu, const char *name)
+{
+ struct perf_pmu_caps *caps;
+
+ list_for_each_entry(caps, &pmu->caps, list) {
+ if (!strcmp(caps->name, name))
+ return caps;
+ }
+ return NULL;
+}
+
/*
* Reading/parsing the given pmu capabilities, which should be located at:
* /sys/bus/event_source/devices/<dev>/caps as sysfs group attributes.
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index dbed6c243a5e..b3d4d7c5b92d 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -266,6 +266,8 @@ bool pmu_uncore_identifier_match(const char *compat, const char *id);
int perf_pmu__convert_scale(const char *scale, char **end, double *sval);
+struct perf_pmu_caps *perf_pmu__get_cap(struct perf_pmu *pmu, const char *name);
+
int perf_pmu__caps_parse(struct perf_pmu *pmu);
void perf_pmu__warn_invalid_config(struct perf_pmu *pmu, __u64 config,
--
2.43.0
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