From: Tomasz Duszynski <tduszyn...@marvell.com>
In order to profile app, one needs to store significant amount of samples
somewhere for an analysis later on.
Since trace library supports storing data in a CTF format,
lets take advantage of that and add a dedicated PMU tracepoint.
Signed-off-by: Tomasz Duszynski <tduszyn...@marvell.com>
---
v17 was merged without this last patch.
It is largely rebased but not compiling.
Feel free to complete the work.
Impact on AMD and unsupported archs must be checked carefully.
---
MAINTAINERS | 1 +
app/test/test_trace_perf.c | 10 ++++
doc/guides/prog_guide/profile_app.rst | 5 ++
doc/guides/prog_guide/trace_lib.rst | 31 +++++++++++
doc/guides/rel_notes/release_25_07.rst | 2 +
lib/eal/common/eal_common_trace.c | 5 +-
lib/eal/common/eal_common_trace_pmu.c | 37 +++++++++++++
lib/eal/common/eal_common_trace_points.c | 5 ++
lib/eal/common/eal_trace.h | 4 ++
lib/eal/common/meson.build | 1 +
lib/eal/include/rte_eal_trace.h | 12 +++++
lib/eal/meson.build | 3 ++
lib/meson.build | 2 +-
lib/pmu/pmu.c | 69 +++++++++++++++++++++++-
lib/pmu/rte_pmu.h | 24 +++++++++
15 files changed, 207 insertions(+), 4 deletions(-)
create mode 100644 lib/eal/common/eal_common_trace_pmu.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 7ed7abb038..43c577e0f1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1851,6 +1851,7 @@ F: doc/guides/prog_guide/eventdev/dispatcher_lib.rst
PMU - EXPERIMENTAL
M: Tomasz Duszynski <tduszyn...@marvell.com>
F: lib/pmu/
+F: lib/eal/common/eal_common_trace_pmu.c
F: app/test/test_pmu.c
Job statistics
diff --git a/app/test/test_trace_perf.c b/app/test/test_trace_perf.c
index 8257cc02be..a45fe15b32 100644
--- a/app/test/test_trace_perf.c
+++ b/app/test/test_trace_perf.c
@@ -114,6 +114,10 @@ worker_fn_##func(void *arg) \
#define GENERIC_DOUBLE rte_eal_trace_generic_double(3.66666)
#define GENERIC_STR rte_eal_trace_generic_str("hello world")
#define VOID_FP app_dpdk_test_fp()
+#ifdef RTE_PMU_SUPPORTED
+/* 0 corresponds first event passed via --trace= */
+#define READ_PMU rte_pmu_trace_read(0)
+#endif
WORKER_DEFINE(GENERIC_VOID)
WORKER_DEFINE(GENERIC_U64)
@@ -122,6 +126,9 @@ WORKER_DEFINE(GENERIC_FLOAT)
WORKER_DEFINE(GENERIC_DOUBLE)
WORKER_DEFINE(GENERIC_STR)
WORKER_DEFINE(VOID_FP)
+#ifdef RTE_PMU_SUPPORTED
+WORKER_DEFINE(READ_PMU)
+#endif
static void
run_test(const char *str, lcore_function_t f, struct test_data *data, size_t
sz)
@@ -174,6 +181,9 @@ test_trace_perf(void)
run_test("double", worker_fn_GENERIC_DOUBLE, data, sz);
run_test("string", worker_fn_GENERIC_STR, data, sz);
run_test("void_fp", worker_fn_VOID_FP, data, sz);
+#ifdef RTE_PMU_SUPPORTED
+ run_test("read_pmu", worker_fn_READ_PMU, data, sz);
+#endif
rte_free(data);
return TEST_SUCCESS;
diff --git a/doc/guides/prog_guide/profile_app.rst
b/doc/guides/prog_guide/profile_app.rst
index 2f47680d5d..362fd20143 100644
--- a/doc/guides/prog_guide/profile_app.rst
+++ b/doc/guides/prog_guide/profile_app.rst
@@ -42,6 +42,11 @@ Current implementation imposes certain limitations:
* EAL lcores must not share a CPU.
* Each EAL lcore measures the same group of events.
+Alternatively tracing library can be used,
+which offers dedicated tracepoint ``rte_pmu_trace_read()``.
+
+Refer to :doc:`../prog_guide/trace_lib` for more details.
+
Profiling on x86
----------------
diff --git a/doc/guides/prog_guide/trace_lib.rst
b/doc/guides/prog_guide/trace_lib.rst
index d9b17abe90..97158cce37 100644
--- a/doc/guides/prog_guide/trace_lib.rst
+++ b/doc/guides/prog_guide/trace_lib.rst
@@ -46,6 +46,7 @@ DPDK tracing library features
trace format and is compatible with ``LTTng``.
For detailed information, refer to
`Common Trace Format <https://diamon.org/ctf/>`_.
+- Support reading PMU events on ARM64 and x86-64 (Intel)
How to add a tracepoint?
------------------------
@@ -139,6 +140,36 @@ the user must use ``RTE_TRACE_POINT_FP`` instead of
``RTE_TRACE_POINT``.
``RTE_TRACE_POINT_FP`` is compiled out by default and it can be enabled using
the ``enable_trace_fp`` option for meson build.
+PMU tracepoint
+--------------
+
+Performance Monitoring Unit (PMU) event values can be read from hardware
registers
+using the predefined ``rte_pmu_read`` tracepoint.
+
+Tracing is enabled via ``--trace`` EAL option by passing both expression
+matching PMU tracepoint name i.e ``lib.eal.pmu.read``
+and expression ``e=ev1[,ev2,...]`` matching particular events::
+
+ --trace='.*pmu.read\|e=cpu_cycles,l1d_cache'
+
+Event names are available under ``/sys/bus/event_source/devices/PMU/events``
directory,
+where ``PMU`` is a placeholder for either a ``cpu`` or a directory containing
``cpus``.
+
+In contrary to other tracepoints this does not need any extra variables
+added to source files.
+Instead, caller passes index
+which follows the order of events specified via ``--trace`` parameter.
+In the following example, index ``0`` corresponds to ``cpu_cyclces``,
+while index ``1`` corresponds to ``l1d_cache``.
+
+.. code-block:: c
+
+ rte_pmu_trace_read(0);
+ rte_pmu_trace_read(1);
+
+PMU tracing support must be explicitly enabled
+using the ``enable_trace_fp`` option for Meson build.
+
Event record mode
-----------------
diff --git a/doc/guides/rel_notes/release_25_07.rst
b/doc/guides/rel_notes/release_25_07.rst
index f23ddb25a4..05ecb23f1f 100644
--- a/doc/guides/rel_notes/release_25_07.rst
+++ b/doc/guides/rel_notes/release_25_07.rst
@@ -59,6 +59,8 @@ New Features
Added a Performance Monitoring Unit (PMU) library which allows Linux
applications
to perform self monitoring activities without depending on external
utilities like perf.
+ After integration with :doc:`../prog_guide/trace_lib`, data gathered from
hardware counters
+ can be stored in CTF format for further analysis.
* **Added Mucse rnp net driver.**
diff --git a/lib/eal/common/eal_common_trace.c
b/lib/eal/common/eal_common_trace.c
index be1f78a68d..45e7f9aa56 100644
--- a/lib/eal/common/eal_common_trace.c
+++ b/lib/eal/common/eal_common_trace.c
@@ -75,8 +75,10 @@ eal_trace_init(void)
goto free_meta;
/* Apply global configurations */
- STAILQ_FOREACH(arg, &trace.args, next)
+ STAILQ_FOREACH(arg, &trace.args, next) {
trace_args_apply(arg->val);
+ trace_pmu_args_apply(arg->val);
+ }
rte_trace_mode_set(trace.mode);
@@ -92,6 +94,7 @@ eal_trace_init(void)
void
eal_trace_fini(void)
{
+ trace_pmu_args_free();
trace_mem_free();
trace_metadata_destroy();
eal_trace_args_free();
diff --git a/lib/eal/common/eal_common_trace_pmu.c
b/lib/eal/common/eal_common_trace_pmu.c
new file mode 100644
index 0000000000..ffab869b10
--- /dev/null
+++ b/lib/eal/common/eal_common_trace_pmu.c
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(C) 2025 Marvell International Ltd.
+ */
+
+#include <rte_common.h>
+#include <rte_pmu.h>
+
+#include "eal_trace.h"
+
+#ifdef RTE_PMU_SUPPORTED
+
+void
+trace_pmu_args_apply(const char *arg)
+{
+ static bool once;
+
+ if (!once) {
+ if (rte_pmu_init())
+ return;
+ once = true;
+ }
+
+ rte_pmu_add_events_by_pattern(arg);
+}
+
+void
+trace_pmu_args_free(void)
+{
+ rte_pmu_fini();
+}
+
+#else /* !RTE_PMU_SUPPORTED */
+
+void trace_pmu_args_apply(const char *arg __rte_unused) { return; }
+void trace_pmu_args_free(void) { return; }
+
+#endif /* RTE_PMU_SUPPORTED */
diff --git a/lib/eal/common/eal_common_trace_points.c
b/lib/eal/common/eal_common_trace_points.c
index 0903f3c639..2531b704f7 100644
--- a/lib/eal/common/eal_common_trace_points.c
+++ b/lib/eal/common/eal_common_trace_points.c
@@ -119,3 +119,8 @@ RTE_TRACE_POINT_REGISTER(rte_eal_trace_intr_enable,
lib.eal.intr.enable)
RTE_TRACE_POINT_REGISTER(rte_eal_trace_intr_disable,
lib.eal.intr.disable)
+
+#if defined(ALLOW_EXPERIMENTAL_API) && defined(RTE_PMU_SUPPORTED)
+RTE_TRACE_POINT_REGISTER(rte_pmu_trace_read,
+ lib.pmu.read)
+#endif
diff --git a/lib/eal/common/eal_trace.h b/lib/eal/common/eal_trace.h
index 55262677e0..58fa43472a 100644
--- a/lib/eal/common/eal_trace.h
+++ b/lib/eal/common/eal_trace.h
@@ -104,6 +104,10 @@ int trace_epoch_time_save(void);
void trace_mem_free(void);
void trace_mem_per_thread_free(void);
+/* PMU wrappers */
+void trace_pmu_args_apply(const char *arg);
+void trace_pmu_args_free(void);
+
/* EAL interface */
int eal_trace_init(void);
void eal_trace_fini(void);
diff --git a/lib/eal/common/meson.build b/lib/eal/common/meson.build
index e273745e93..239c111461 100644
--- a/lib/eal/common/meson.build
+++ b/lib/eal/common/meson.build
@@ -28,6 +28,7 @@ sources += files(
'eal_common_tailqs.c',
'eal_common_thread.c',
'eal_common_timer.c',
+ 'eal_common_trace_pmu.c',
'eal_common_trace_points.c',
'eal_common_uuid.c',
'malloc_elem.c',
diff --git a/lib/eal/include/rte_eal_trace.h b/lib/eal/include/rte_eal_trace.h
index 9ad2112801..4ed9159514 100644
--- a/lib/eal/include/rte_eal_trace.h
+++ b/lib/eal/include/rte_eal_trace.h
@@ -127,6 +127,18 @@ RTE_TRACE_POINT(
#define RTE_EAL_TRACE_GENERIC_FUNC rte_eal_trace_generic_func(__func__)
+#ifdef ALLOW_EXPERIMENTAL_API
+#include <rte_pmu.h>
+#ifdef RTE_PMU_SUPPORTED
+RTE_TRACE_POINT_FP(
+ rte_pmu_trace_read,
+ RTE_TRACE_POINT_ARGS(unsigned int index),
+ uint64_t val = rte_pmu_read(index);
+ rte_trace_point_emit_u64(val);
+)
+#endif
+#endif
+
#ifdef __cplusplus
}
#endif
diff --git a/lib/eal/meson.build b/lib/eal/meson.build
index e1d6c4cf17..c46893aeaa 100644
--- a/lib/eal/meson.build
+++ b/lib/eal/meson.build
@@ -15,6 +15,9 @@ subdir(exec_env)
subdir(arch_subdir)
deps += ['log', 'kvargs']
+if is_linux
+ deps += ['pmu']
+endif
if not is_windows
deps += ['telemetry']
endif
diff --git a/lib/meson.build b/lib/meson.build
index 1934cb4a29..87b567f01b 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -13,7 +13,7 @@ libraries = [
'kvargs', # eal depends on kvargs
'argparse',
'telemetry', # basic info querying
- 'pmu',
+ 'pmu', # trace depends on pmu
'eal', # everything depends on eal
'ptr_compress',
'ring',
diff --git a/lib/pmu/pmu.c b/lib/pmu/pmu.c
index 46b0b450ac..35ea451863 100644
--- a/lib/pmu/pmu.c
+++ b/lib/pmu/pmu.c
@@ -4,6 +4,7 @@
#include <errno.h>
#include <ctype.h>
+#include <regex.h>
#include <dirent.h>
#include <stdlib.h>
#include <unistd.h>
@@ -408,13 +409,77 @@ rte_pmu_add_event(const char *name)
return event->index;
}
+static int
+add_events(const char *pattern)
+{
+ char *token, *copy, *tmp;
+ int ret = 0;
+
+ copy = strdup(pattern);
+ if (copy == NULL)
+ return -ENOMEM;
+
+ token = strtok_r(copy, ",", &tmp);
+ while (token) {
+ ret = rte_pmu_add_event(token);
+ if (ret < 0)
+ break;
+
+ token = strtok_r(NULL, ",", &tmp);
+ }
+
+ free(copy);
+
+ return ret >= 0 ? 0 : ret;
+}
+
+RTE_EXPORT_EXPERIMENTAL_SYMBOL(rte_pmu_add_events_by_pattern, 25.07)
+int
+rte_pmu_add_events_by_pattern(const char *pattern)
+{
+ regmatch_t rmatch;
+ char buf[BUFSIZ];
+ unsigned int num;
+ regex_t reg;
+ int ret;
+
+ /* events are matched against occurrences of e=ev1[,ev2,..] pattern */
+ ret = regcomp(®, "e=([_[:alnum:]-],?)+", REG_EXTENDED);
+ if (ret) {
+ PMU_LOG(ERR, "Failed to compile event matching regexp");
+ return -EINVAL;
+ }
+
+ for (;;) {
+ if (regexec(®, pattern, 1, &rmatch, 0))
+ break;
+
+ num = rmatch.rm_eo - rmatch.rm_so;
+ if (num > sizeof(buf))
+ num = sizeof(buf);
+
+ /* skip e= pattern prefix */
+ memcpy(buf, pattern + rmatch.rm_so + 2, num - 2);
+ buf[num - 2] = '\0';
+ ret = add_events(buf);
+ if (ret)
+ break;
+
+ pattern += rmatch.rm_eo;
+ }
+
+ regfree(®);
+
+ return ret;
+}
+
RTE_EXPORT_EXPERIMENTAL_SYMBOL(rte_pmu_init, 25.07)
int
rte_pmu_init(void)
{
int ret;
- if (rte_pmu.initialized)
+ if (rte_pmu.initialized && ++rte_pmu.initialized)
return 0;
ret = scan_pmus();
@@ -448,7 +513,7 @@ rte_pmu_fini(void)
struct rte_pmu_event_group *group;
unsigned int i;
- if (!rte_pmu.initialized)
+ if (!rte_pmu.initialized || --rte_pmu.initialized)
return;
RTE_TAILQ_FOREACH_SAFE(event, &rte_pmu.event_list, next, tmp_event) {
diff --git a/lib/pmu/rte_pmu.h b/lib/pmu/rte_pmu.h
index 57b634ecd8..c11c39fb09 100644
--- a/lib/pmu/rte_pmu.h
+++ b/lib/pmu/rte_pmu.h
@@ -21,6 +21,10 @@
*
* rte_pmu_init()
* rte_pmu_add_event()
+ * rte_pmu_add_event() [or rte_pmu_add_events_by_pattern()]
+ *
+ * Note that if -Denable_trace_fp=True was passed to Meson,
+ * rte_pmu_init() gets called automatically.
*
* Afterwards all threads can read events by calling rte_pmu_read().
*/
@@ -148,6 +152,8 @@ __rte_pmu_enable_group(struct rte_pmu_event_group *group);
*
* Initialize PMU library.
*
+ * It's safe to call it multiple times.
+ *
* @return
* 0 in case of success, negative value otherwise.
*/
@@ -160,6 +166,9 @@ rte_pmu_init(void);
* @b EXPERIMENTAL: this API may change without prior notice.
*
* Finalize PMU library.
+ *
+ * Number of calls must match number of times rte_pmu_init() was called.
+ * Otherwise memory won't be freed properly.
*/
__rte_experimental
void
@@ -187,6 +196,21 @@ rte_pmu_add_event(const char *name);
#define __rte_pmu_read_userpage(pc) ({ RTE_SET_USED(pc); 0; })
#endif
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Add events matching pattern to the group of enabled events.
+ *
+ * @param pattern
+ * Pattern e=ev1[,ev2,...] matching events
+ * listed under /sys/bus/event_source/devices/pmu/events,
+ * where evX and PMU are placeholders for respectively an event and an event
source.
+ */
+__rte_experimental
+int
+rte_pmu_add_events_by_pattern(const char *pattern);
+
/**
* @warning
* @b EXPERIMENTAL: this API may change without prior notice.
--
2.47.1
