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>
---
app/test/test_trace_perf.c | 10 ++++
doc/guides/prog_guide/profile_app.rst | 5 ++
doc/guides/prog_guide/trace_lib.rst | 32 +++++++++++
lib/eal/common/eal_common_trace.c | 5 +-
lib/eal/common/eal_common_trace_pmu.c | 38 ++++++++++++++
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 | 11 ++++
lib/eal/version.map | 1 +
lib/pmu/rte_pmu.c | 67 +++++++++++++++++++++++-
lib/pmu/rte_pmu.h | 24 +++++++--
lib/pmu/version.map | 1 +
13 files changed, 198 insertions(+), 6 deletions(-)
create mode 100644 lib/eal/common/eal_common_trace_pmu.c
diff --git a/app/test/test_trace_perf.c b/app/test/test_trace_perf.c
index 8257cc02be..8a0730943e 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_LIB_PMU
+/* 0 corresponds first event passed via --trace= */
+#define READ_PMU rte_eal_trace_pmu_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_LIB_PMU
+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_LIB_PMU
+ 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 854c515a61..1ab6fb9eaa 100644
--- a/doc/guides/prog_guide/profile_app.rst
+++ b/doc/guides/prog_guide/profile_app.rst
@@ -36,6 +36,11 @@ As of now implementation imposes certain limitations:
* Each EAL lcore measures same group of events
+Alternatively tracing library can be used which offers dedicated tracepoint
+``rte_eal_trace_pmu_event()``.
+
+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..378abccd72 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 +140,37 @@ 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 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_eal_trace_pmu_read(0);
+ rte_eal_trace_pmu_read(1);
+ ...
+
+PMU tracing support must be explicitly enabled using the ``enable_trace_fp``
+option for meson build.
+
Event record mode
-----------------
diff --git a/lib/eal/common/eal_common_trace.c
b/lib/eal/common/eal_common_trace.c
index 918f49bf4f..9be8724ec4 100644
--- a/lib/eal/common/eal_common_trace.c
+++ b/lib/eal/common/eal_common_trace.c
@@ -72,8 +72,10 @@ 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);
@@ -89,6 +91,7 @@ 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..b3ab41e8a2
--- /dev/null
+++ b/lib/eal/common/eal_common_trace_pmu.c
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(C) 2024 Marvell International Ltd.
+ */
+
+#include <rte_common.h>
+
+#include "eal_trace.h"
+
+#ifdef RTE_LIB_PMU
+
+#include <rte_pmu.h>
+
+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_LIB_PMU */
+
+void trace_pmu_args_apply(const char *arg __rte_unused) { return; }
+void trace_pmu_args_free(void) { return; }
+
+#endif /* RTE_LIB_PMU */
diff --git a/lib/eal/common/eal_common_trace_points.c
b/lib/eal/common/eal_common_trace_points.c
index 0f1240ea3a..c99eab92f4 100644
--- a/lib/eal/common/eal_common_trace_points.c
+++ b/lib/eal/common/eal_common_trace_points.c
@@ -100,3 +100,8 @@ 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)
+
+#ifdef RTE_LIB_PMU
+RTE_TRACE_POINT_REGISTER(rte_eal_trace_pmu_read,
+ lib.eal.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 c1bbf26654..59d5b15708 100644
--- a/lib/eal/common/meson.build
+++ b/lib/eal/common/meson.build
@@ -27,6 +27,7 @@ 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..9c78f63ff5 100644
--- a/lib/eal/include/rte_eal_trace.h
+++ b/lib/eal/include/rte_eal_trace.h
@@ -127,6 +127,17 @@ RTE_TRACE_POINT(
#define RTE_EAL_TRACE_GENERIC_FUNC rte_eal_trace_generic_func(__func__)
+#ifdef RTE_LIB_PMU
+#include <rte_pmu.h>
+
+RTE_TRACE_POINT_FP(
+ rte_eal_trace_pmu_read,
+ RTE_TRACE_POINT_ARGS(unsigned int index),
+ uint64_t val = rte_pmu_read(index);
+ rte_trace_point_emit_u64(val);
+)
+#endif
+
#ifdef __cplusplus
}
#endif
diff --git a/lib/eal/version.map b/lib/eal/version.map
index f493cd1ca7..3dc147f848 100644
--- a/lib/eal/version.map
+++ b/lib/eal/version.map
@@ -399,6 +399,7 @@ EXPERIMENTAL {
# added in 24.11
rte_bitset_to_str;
+ __rte_eal_trace_pmu_read; # WINDOWS_NO_EXPORT
};
INTERNAL {
diff --git a/lib/pmu/rte_pmu.c b/lib/pmu/rte_pmu.c
index dd57961627..b65f08c75b 100644
--- a/lib/pmu/rte_pmu.c
+++ b/lib/pmu/rte_pmu.c
@@ -412,12 +412,75 @@ rte_pmu_add_event(const char *name)
return event->index;
}
+static int
+add_events(const char *pattern)
+{
+ char *token, *copy;
+ int ret = 0;
+
+ copy = strdup(pattern);
+ if (copy == NULL)
+ return -ENOMEM;
+
+ token = strtok(copy, ",");
+ while (token) {
+ ret = rte_pmu_add_event(token);
+ if (ret < 0)
+ break;
+
+ token = strtok(NULL, ",");
+ }
+
+ free(copy);
+
+ return ret >= 0 ? 0 : ret;
+}
+
+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;
+}
+
int
rte_pmu_init(void)
{
int ret;
- if (rte_pmu.initialized)
+ if (rte_pmu.initialized && ++rte_pmu.initialized)
return 0;
ret = scan_pmus();
@@ -450,7 +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 85f9127911..df571f0a2f 100644
--- a/lib/pmu/rte_pmu.h
+++ b/lib/pmu/rte_pmu.h
@@ -135,7 +135,7 @@ __rte_pmu_enable_group(struct rte_pmu_event_group *group);
* @warning
* @b EXPERIMENTAL: this API may change without prior notice
*
- * Initialize PMU library.
+ * Initialize PMU library. It's safe to call it multiple times.
*
* @return
* 0 in case of success, negative value otherwise.
@@ -148,7 +148,9 @@ rte_pmu_init(void);
* @warning
* @b EXPERIMENTAL: this API may change without prior notice
*
- * Finalize PMU library.
+ * 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
@@ -173,7 +175,23 @@ rte_pmu_add_event(const char *name);
* @warning
* @b EXPERIMENTAL: this API may change without prior notice
*
- * Read hardware counter configured to count occurrences of an event.
+ * Add events matching pattern to the group of enabled events.
+ *
+ * @param pattern
+ * Pattern e=ev1[,ev2,...] matching events, where evX is a placeholder for
an event listed under
+ * /sys/bus/event_source/devices/<pmu>/events.
+ */
+__rte_experimental
+int
+rte_pmu_add_events_by_pattern(const char *pattern);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Read hardware counter configured to count occurrences of an event. This is
called by an lcore
+ * binded exclusively to particular cpu and may not work as expected if gets
migrated elsewhere.
+ * Reason being event group is pinned hence not supposed to be multiplexed
with any other events.
*
* @param index
* Index of an event to be read.
diff --git a/lib/pmu/version.map b/lib/pmu/version.map
index d0f907d13d..f14d498b54 100644
--- a/lib/pmu/version.map
+++ b/lib/pmu/version.map
@@ -5,6 +5,7 @@ EXPERIMENTAL {
__rte_pmu_enable_group;
rte_pmu;
rte_pmu_add_event;
+ rte_pmu_add_events_by_pattern;
rte_pmu_fini;
rte_pmu_init;
rte_pmu_read;
--
2.34.1
