2022-02-25 12:01:36

by [email protected]

[permalink] [raw]
Subject: [RFC PATCH 0/7] libperf: Add overflow detection of sampling events

From: Shunsuke Nakamura <[email protected]>

This patch series adds sampling event overflow detection capability
to libperf.

First patch fixes a typo in the error message that I noticed.

Second patch adds a interface to set PERF_FLAG_FD_CLOEXEC

Third patch adds a interface to perform IOC_REFRESH and IOC_PERIOD.

Fourth patch adds a interface to set the signal handler.

Fifth patch adds a interface to detect overflowed events.

Sixth and seventh patch adds tests.

Shunsuke Nakamura (7):
libperf tests: Fix typo in the error message "evsel" -> "evlist"
libperf: Add perf_evsel__set_close_on_exec() function
libperf: Add perf_evsel__refresh()/period() functions
libperf: Add perf_evsel__set_signal() functions
libperf: Add perf_evsel__check_fd() functions
libperf test: Add test_stat_overflow()
libperf test: Add test_detect_overflow_event()

tools/lib/perf/Documentation/libperf.txt | 12 ++
tools/lib/perf/evsel.c | 215 ++++++++++++++++++++++-
tools/lib/perf/include/internal/evsel.h | 2 +
tools/lib/perf/include/perf/evsel.h | 14 ++
tools/lib/perf/libperf.map | 9 +
tools/lib/perf/tests/test-evlist.c | 127 ++++++++++++-
tools/lib/perf/tests/test-evsel.c | 110 ++++++++++++
tools/perf/util/evsel.c | 16 +-
tools/perf/util/evsel.h | 1 -
9 files changed, 487 insertions(+), 19 deletions(-)

--
2.31.1


2022-02-25 13:11:26

by [email protected]

[permalink] [raw]
Subject: [RFC PATCH 2/7] libperf: Add perf_evsel__set_close_on_exec() function

From: Shunsuke Nakamura <[email protected]>

Move evsel::open_flags to perf_evsel::open_flags and add a function to
set PERF_FLAG_FD_CLOEXEC.

Signed-off-by: Shunsuke Nakamura <[email protected]>
---
tools/lib/perf/Documentation/libperf.txt | 1 +
tools/lib/perf/evsel.c | 15 ++++++++++++++-
tools/lib/perf/include/internal/evsel.h | 2 ++
tools/lib/perf/include/perf/evsel.h | 1 +
tools/lib/perf/libperf.map | 1 +
tools/perf/util/evsel.c | 16 +++++++++-------
tools/perf/util/evsel.h | 1 -
7 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
index 32c5051c24eb..96a451cd34eb 100644
--- a/tools/lib/perf/Documentation/libperf.txt
+++ b/tools/lib/perf/Documentation/libperf.txt
@@ -149,6 +149,7 @@ SYNOPSIS
struct perf_cpu_map *perf_evsel__cpus(struct perf_evsel *evsel);
struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel);
struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
+ int perf_evsel__set_close_on_exec(struct perf_evsel *evsel);
--

*API to handle maps (perf ring buffers):*
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index 210ea7c06ce8..d22b1468a1ad 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -26,6 +26,7 @@ void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
evsel->attr = *attr;
evsel->idx = idx;
evsel->leader = evsel;
+ evsel->open_flags = 0;
}

struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr)
@@ -158,7 +159,7 @@ int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,

fd = sys_perf_event_open(&evsel->attr,
threads->map[thread].pid,
- cpu, group_fd, 0);
+ cpu, group_fd, evsel->open_flags);

if (fd < 0)
return -errno;
@@ -454,3 +455,15 @@ void perf_counts_values__scale(struct perf_counts_values *count,
if (pscaled)
*pscaled = scaled;
}
+
+int perf_evsel__set_close_on_exec(struct perf_evsel *evsel)
+{
+ int err = 0;
+
+ if (evsel)
+ evsel->open_flags |= PERF_FLAG_FD_CLOEXEC;
+ else
+ err = -1;
+
+ return err;
+}
diff --git a/tools/lib/perf/include/internal/evsel.h b/tools/lib/perf/include/internal/evsel.h
index cfc9ebd7968e..37a99cf261b3 100644
--- a/tools/lib/perf/include/internal/evsel.h
+++ b/tools/lib/perf/include/internal/evsel.h
@@ -51,6 +51,8 @@ struct perf_evsel {
int nr_members;
bool system_wide;
int idx;
+
+ unsigned long open_flags;
};

void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h
index 2a9516b42d15..23b0334a4c57 100644
--- a/tools/lib/perf/include/perf/evsel.h
+++ b/tools/lib/perf/include/perf/evsel.h
@@ -43,5 +43,6 @@ LIBPERF_API struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel
LIBPERF_API struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
LIBPERF_API void perf_counts_values__scale(struct perf_counts_values *count,
bool scale, __s8 *pscaled);
+LIBPERF_API int perf_evsel__set_close_on_exec(struct perf_evsel *evsel);

#endif /* __LIBPERF_EVSEL_H */
diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
index 93696affda2e..0f8d13f9009b 100644
--- a/tools/lib/perf/libperf.map
+++ b/tools/lib/perf/libperf.map
@@ -52,6 +52,7 @@ LIBPERF_0.0.1 {
perf_mmap__read_done;
perf_mmap__read_event;
perf_counts_values__scale;
+ perf_evsel__set_close_on_exec;
local:
*;
};
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 22d3267ce294..52c34552ee76 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1794,9 +1794,9 @@ static int __evsel__prepare_open(struct evsel *evsel, struct perf_cpu_map *cpus,
perf_evsel__alloc_fd(&evsel->core, perf_cpu_map__nr(cpus), nthreads) < 0)
return -ENOMEM;

- evsel->open_flags = PERF_FLAG_FD_CLOEXEC;
+ evsel->core.open_flags = PERF_FLAG_FD_CLOEXEC;
if (evsel->cgrp)
- evsel->open_flags |= PERF_FLAG_PID_CGROUP;
+ evsel->core.open_flags |= PERF_FLAG_PID_CGROUP;

return 0;
}
@@ -1814,7 +1814,7 @@ static void evsel__disable_missing_features(struct evsel *evsel)
evsel->core.attr.clockid = 0;
}
if (perf_missing_features.cloexec)
- evsel->open_flags &= ~(unsigned long)PERF_FLAG_FD_CLOEXEC;
+ evsel->core.open_flags &= ~(unsigned long)PERF_FLAG_FD_CLOEXEC;
if (perf_missing_features.mmap2)
evsel->core.attr.mmap2 = 0;
if (evsel->pmu && evsel->pmu->missing_features.exclude_guest)
@@ -1902,7 +1902,8 @@ bool evsel__detect_missing_features(struct evsel *evsel)
perf_missing_features.clockid = true;
pr_debug2_peo("switching off use_clockid\n");
return true;
- } else if (!perf_missing_features.cloexec && (evsel->open_flags & PERF_FLAG_FD_CLOEXEC)) {
+ } else if (!perf_missing_features.cloexec &&
+ (evsel->core.open_flags & PERF_FLAG_FD_CLOEXEC)) {
perf_missing_features.cloexec = true;
pr_debug2_peo("switching off cloexec flag\n");
return true;
@@ -2029,11 +2030,12 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
test_attr__ready();

pr_debug2_peo("sys_perf_event_open: pid %d cpu %d group_fd %d flags %#lx",
- pid, perf_cpu_map__cpu(cpus, idx).cpu, group_fd, evsel->open_flags);
+ pid, perf_cpu_map__cpu(cpus, idx).cpu, group_fd,
+ evsel->core.open_flags);

fd = sys_perf_event_open(&evsel->core.attr, pid,
perf_cpu_map__cpu(cpus, idx).cpu,
- group_fd, evsel->open_flags);
+ group_fd, evsel->core.open_flags);

FD(evsel, idx, thread) = fd;

@@ -2050,7 +2052,7 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus,
if (unlikely(test_attr__enabled)) {
test_attr__open(&evsel->core.attr, pid,
perf_cpu_map__cpu(cpus, idx),
- fd, group_fd, evsel->open_flags);
+ fd, group_fd, evsel->core.open_flags);
}

pr_debug2_peo(" = %d\n", fd);
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 041b42d33bf5..8a545954eec7 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -152,7 +152,6 @@ struct evsel {
struct bperf_leader_bpf *leader_skel;
struct bperf_follower_bpf *follower_skel;
};
- unsigned long open_flags;
int precise_ip_original;

/* for missing_features */
--
2.31.1

2022-02-25 13:31:43

by [email protected]

[permalink] [raw]
Subject: [RFC PATCH 1/7] libperf tests: Fix typo in the error message "evsel" -> "evlist"

From: Shunsuke Nakamura <[email protected]>

This patch corrects a typo in the error message.

Signed-off-by: Shunsuke Nakamura <[email protected]>
---
tools/lib/perf/tests/test-evlist.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/lib/perf/tests/test-evlist.c b/tools/lib/perf/tests/test-evlist.c
index b3479dfa9a1c..fafc6b0f8687 100644
--- a/tools/lib/perf/tests/test-evlist.c
+++ b/tools/lib/perf/tests/test-evlist.c
@@ -68,7 +68,7 @@ static int test_stat_cpu(void)
perf_evlist__set_maps(evlist, cpus, NULL);

err = perf_evlist__open(evlist);
- __T("failed to open evsel", err == 0);
+ __T("failed to open evlist", err == 0);

perf_evlist__for_each_evsel(evlist, evsel) {
cpus = perf_evsel__cpus(evsel);
@@ -129,7 +129,7 @@ static int test_stat_thread(void)
perf_evlist__set_maps(evlist, NULL, threads);

err = perf_evlist__open(evlist);
- __T("failed to open evsel", err == 0);
+ __T("failed to open evlist", err == 0);

perf_evlist__for_each_evsel(evlist, evsel) {
perf_evsel__read(evsel, 0, 0, &counts);
@@ -186,7 +186,7 @@ static int test_stat_thread_enable(void)
perf_evlist__set_maps(evlist, NULL, threads);

err = perf_evlist__open(evlist);
- __T("failed to open evsel", err == 0);
+ __T("failed to open evlist", err == 0);

perf_evlist__for_each_evsel(evlist, evsel) {
perf_evsel__read(evsel, 0, 0, &counts);
@@ -506,7 +506,7 @@ static int test_stat_multiplexing(void)
perf_evlist__set_maps(evlist, NULL, threads);

err = perf_evlist__open(evlist);
- __T("failed to open evsel", err == 0);
+ __T("failed to open evlist", err == 0);

perf_evlist__enable(evlist);

--
2.31.1

2022-02-25 13:42:10

by [email protected]

[permalink] [raw]
Subject: [RFC PATCH 6/7] libperf test: Add test_stat_overflow()

From: Shunsuke Nakamura <[email protected]>

Added tests using refresh and period.

Confirmation
- That the overflow occurs the number of times specified by
perf_evse__refresh()
- That the period can be updated by perf_evsel__period()

Committer testing:

$ sudo make tests -C tools/lib/perf/ V=1
make: Entering directory '/home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/lib/perf'
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=. obj=libperf
make -C /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/lib/api/ O= libapi.a
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=./fd obj=libapi
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=./fs obj=libapi
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=. obj=tests
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=./tests obj=tests
running static:
- running tests/test-cpumap.c...OK
- running tests/test-threadmap.c...OK
- running tests/test-evlist.c...

<SNIP>

OK
- running tests/test-evsel.c...
loop = 65536, count = 330818
loop = 131072, count = 662958
loop = 262144, count = 1316088
loop = 524288, count = 2632699
loop = 1048576, count = 5254501
loop = 65536, count = 348709
loop = 131072, count = 694239
loop = 262144, count = 1370888
loop = 524288, count = 2744824
loop = 1048576, count = 5465047
period = 1000000
overflow limit = 3, overflow count = 3POLL_IN = 2, POLL_UP = 1, other signal event = 0
period = 2000000
overflow limit = 3, overflow count = 3POLL_IN = 2, POLL_UP = 1, other signal event = 0
period = 1000000
overflow limit = 3, overflow count = 3POLL_IN = 2, POLL_UP = 1, other signal event = 0
period = 2000000
overflow limit = 3, overflow count = 3POLL_IN = 2, POLL_UP = 1, other signal event = 0
OK
running dynamic:
- running tests/test-cpumap.c...OK
- running tests/test-threadmap.c...OK
- running tests/test-evlist.c...

<SNIP>

OK
- running tests/test-evsel.c...
loop = 65536, count = 330819
loop = 131072, count = 662959
loop = 262144, count = 1323589
loop = 524288, count = 2626809
loop = 1048576, count = 5260090
loop = 65536, count = 351641
loop = 131072, count = 697661
loop = 262144, count = 1373234
loop = 524288, count = 2743662
loop = 1048576, count = 5473195
period = 1000000
overflow limit = 3, overflow count = 3POLL_IN = 2, POLL_UP = 1, other signal event = 0
period = 2000000
overflow limit = 3, overflow count = 3POLL_IN = 2, POLL_UP = 1, other signal event = 0
period = 1000000
overflow limit = 3, overflow count = 3POLL_IN = 2, POLL_UP = 1, other signal event = 0
period = 2000000
overflow limit = 3, overflow count = 3POLL_IN = 2, POLL_UP = 1, other signal event = 0
OK
make: Leaving directory '/home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/lib/perf'

Signed-off-by: Shunsuke Nakamura <[email protected]>
---
tools/lib/perf/tests/test-evsel.c | 110 ++++++++++++++++++++++++++++++
1 file changed, 110 insertions(+)

diff --git a/tools/lib/perf/tests/test-evsel.c b/tools/lib/perf/tests/test-evsel.c
index 89be89afb24d..9232b2f25082 100644
--- a/tools/lib/perf/tests/test-evsel.c
+++ b/tools/lib/perf/tests/test-evsel.c
@@ -1,6 +1,14 @@
// SPDX-License-Identifier: GPL-2.0
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <inttypes.h>
#include <stdarg.h>
#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+#include <fcntl.h>
#include <linux/perf_event.h>
#include <perf/cpumap.h>
#include <perf/threadmap.h>
@@ -8,6 +16,15 @@
#include <internal/tests.h>
#include "tests.h"

+#define WAIT_COUNT 10000000UL
+static struct signal_counts {
+ int in;
+ int hup;
+ int others;
+ int overflow;
+} sig_count = {0, 0, 0};
+static struct perf_evsel *s_evsel;
+
static int libperf_print(enum libperf_print_level level,
const char *fmt, va_list ap)
{
@@ -189,6 +206,97 @@ static int test_stat_user_read(int event)
return 0;
}

+static void sig_handler(int signo, siginfo_t *info, void *uc)
+{
+ switch (info->si_code) {
+ case POLL_IN:
+ sig_count.in++;
+ break;
+ case POLL_HUP:
+ sig_count.hup++;
+ break;
+ default:
+ sig_count.others++;
+ }
+
+ sig_count.overflow++;
+}
+
+static int test_stat_refresh(int owner)
+{
+ static struct sigaction sig;
+ u64 period = 1000000;
+ int overflow_limit = 3;
+
+ struct perf_thread_map *threads;
+ struct perf_event_attr attr = {
+ .type = PERF_TYPE_SOFTWARE,
+ .config = PERF_COUNT_SW_TASK_CLOCK,
+ .sample_type = PERF_SAMPLE_PERIOD,
+ .sample_period = period,
+ .disabled = 1,
+ };
+ struct perf_event_attr *tmp_attr;
+ int err, i;
+ unsigned int wait_count;
+
+ /* setup signal handler */
+ memset(&sig, 0, sizeof(struct sigaction));
+ sig.sa_sigaction = (void *)sig_handler;
+ sig.sa_flags = SA_SIGINFO;
+
+ threads = perf_thread_map__new_dummy();
+ __T("failed to create threads", threads);
+
+ perf_thread_map__set_pid(threads, 0, 0);
+
+ s_evsel = perf_evsel__new(&attr);
+ __T("failed to create evsel", s_evsel);
+
+ err = perf_evsel__set_close_on_exec(s_evsel);
+ __T("failed to set PERF_FLAG_FD_CLOEXEC flag to evsel", err == 0);
+
+ err = perf_evsel__open(s_evsel, NULL, threads);
+ __T("failed to open evsel", err == 0);
+
+ err = perf_evsel__set_signal(s_evsel, owner, SIGIO, &sig);
+ __T("failed to set signal", err == 0);
+
+ for (i = 0; i < 2; i++) {
+ period = period << i;
+ err = perf_evsel__period(s_evsel, period);
+ __T("failed to period evsel", err == 0);
+
+ tmp_attr = perf_evsel__attr(s_evsel);
+ __T_VERBOSE("\tperiod = %llu\n", tmp_attr->sample_period);
+
+ err = perf_evsel__refresh(s_evsel, overflow_limit);
+ __T("failed to refresh evsel", err == 0);
+
+ wait_count = WAIT_COUNT;
+ while (wait_count--)
+ ;
+
+ __T_VERBOSE("\toverflow limit = %d, overflow count = %d",
+ overflow_limit, sig_count.overflow);
+ __T_VERBOSE("POLL_IN = %d, POLL_UP = %d, other signal event = %d\n",
+ sig_count.in, sig_count.hup, sig_count.others);
+
+ __T("failed to overflow count", overflow_limit == sig_count.overflow);
+
+ sig_count.in = 0;
+ sig_count.hup = 0;
+ sig_count.others = 0;
+ sig_count.overflow = 0;
+ }
+
+ perf_evsel__close(s_evsel);
+ perf_evsel__delete(s_evsel);
+ perf_thread_map__put(threads);
+
+ return 0;
+}
+
int test_evsel(int argc, char **argv)
{
__T_START;
@@ -200,6 +308,8 @@ int test_evsel(int argc, char **argv)
test_stat_thread_enable();
test_stat_user_read(PERF_COUNT_HW_INSTRUCTIONS);
test_stat_user_read(PERF_COUNT_HW_CPU_CYCLES);
+ test_stat_refresh(F_OWNER_PID);
+ test_stat_refresh(F_OWNER_TID);

__T_END;
return tests_failed == 0 ? 0 : -1;
--
2.31.1

2022-02-25 14:35:48

by [email protected]

[permalink] [raw]
Subject: [RFC PATCH 4/7] libperf: Add perf_evsel__set_signal() functions

From: Shunsuke Nakamura <[email protected]>

Add the following functions:

perf_evsel__set_signal()
perf_evsel__set_signal_cpu()

to set the parameters to get the overflow signal.

Signed-off-by: Shunsuke Nakamura <[email protected]>
---
tools/lib/perf/Documentation/libperf.txt | 4 +
tools/lib/perf/evsel.c | 105 +++++++++++++++++++++++
tools/lib/perf/include/perf/evsel.h | 6 ++
tools/lib/perf/libperf.map | 2 +
4 files changed, 117 insertions(+)

diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
index 8f523293fb9d..d0aa57c6ca97 100644
--- a/tools/lib/perf/Documentation/libperf.txt
+++ b/tools/lib/perf/Documentation/libperf.txt
@@ -151,6 +151,10 @@ SYNOPSIS
int cpu_map_idx);
int perf_evsel__period(struct perf_evsel *evsel, int period);
int perf_evsel__period_cpu(struct perf_evsel *evsel, int period, int cpu_map_idx);
+ int perf_evsel__set_signal(struct perf_evsel *evsel, int owner_type, unsigned int signal,
+ struct sigaction *sig);
+ int perf_evsel__set_signal_cpu(struct perf_evsel *evsel, int owner_type, unsigned int signal,
+ struct sigaction *sig, int cpu_map_idx);
struct perf_cpu_map *perf_evsel__cpus(struct perf_evsel *evsel);
struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel);
struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index 8348545874e4..991ab04112b1 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -1,4 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
#include <errno.h>
#include <unistd.h>
#include <sys/syscall.h>
@@ -16,6 +19,9 @@
#include <internal/lib.h>
#include <linux/string.h>
#include <sys/ioctl.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <sys/types.h>
#include <sys/mman.h>
#include <asm/bug.h>

@@ -351,6 +357,28 @@ static int perf_evsel__run_ioctl(struct perf_evsel *evsel,
return 0;
}

+static int perf_evsel__run_fcntl(struct perf_evsel *evsel,
+ unsigned int cmd, unsigned long arg,
+ int cpu_map_idx)
+{
+ int thread;
+
+ for (thread = 0; thread < xyarray__max_y(evsel->fd); thread++) {
+ int err;
+ int *fd = FD(evsel, cpu_map_idx, thread);
+
+ if (!fd || *fd < 0)
+ return -1;
+
+ err = fcntl(*fd, cmd, arg);
+
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
int perf_evsel__enable_cpu(struct perf_evsel *evsel, int cpu_map_idx)
{
return perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_ENABLE, 0, cpu_map_idx);
@@ -437,6 +465,83 @@ int perf_evsel__period(struct perf_evsel *evsel, __u64 period)
return err;
}

+int perf_evsel__set_signal_cpu(struct perf_evsel *evsel, int owner_type, unsigned int signal,
+ struct sigaction *sig, int cpu_map_idx)
+{
+ int err = 0;
+ struct f_owner_ex owner;
+
+ switch (owner_type) {
+ case F_OWNER_PID:
+ owner.pid = getpid();
+ break;
+ case F_OWNER_TID:
+ owner.pid = syscall(SYS_gettid);
+ break;
+ default:
+ return -1;
+ }
+
+ err = perf_evsel__run_fcntl(evsel, F_SETFL, (O_RDWR | O_NONBLOCK | O_ASYNC), cpu_map_idx);
+ if (err)
+ return err;
+
+ err = perf_evsel__run_fcntl(evsel, F_SETSIG, signal, cpu_map_idx);
+ if (err)
+ return err;
+
+ err = perf_evsel__run_fcntl(evsel, F_SETOWN_EX, (unsigned long)&owner, cpu_map_idx);
+ if (err)
+ return err;
+
+ err = sigaction(signal, sig, NULL);
+ if (err)
+ return err;
+
+ return err;
+}
+
+int perf_evsel__set_signal(struct perf_evsel *evsel, int owner_type, unsigned int signal,
+ struct sigaction *sig)
+{
+ int i;
+ int err = 0;
+ struct f_owner_ex owner;
+
+ switch (owner_type) {
+ case F_OWNER_PID:
+ owner.pid = getpid();
+ break;
+ case F_OWNER_TID:
+ owner.pid = syscall(SYS_gettid);
+ break;
+ default:
+ return -1;
+ }
+
+ owner.type = owner_type;
+
+ for (i = 0; i < xyarray__max_x(evsel->fd) && !err; i++) {
+ err = perf_evsel__run_fcntl(evsel, F_SETFL, (O_RDWR | O_NONBLOCK | O_ASYNC), i);
+ if (err)
+ return err;
+
+ err = perf_evsel__run_fcntl(evsel, F_SETSIG, signal, i);
+ if (err)
+ return err;
+
+ err = perf_evsel__run_fcntl(evsel, F_SETOWN_EX, (unsigned long)&owner, i);
+ if (err)
+ return err;
+ }
+
+ err = sigaction(signal, sig, NULL);
+ if (err)
+ return err;
+
+ return err;
+}
+
int perf_evsel__apply_filter(struct perf_evsel *evsel, const char *filter)
{
int err = 0, i;
diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h
index 9ec24a5f5f9f..15768fc91910 100644
--- a/tools/lib/perf/include/perf/evsel.h
+++ b/tools/lib/perf/include/perf/evsel.h
@@ -5,6 +5,7 @@
#include <stdint.h>
#include <perf/core.h>
#include <stdbool.h>
+#include <signal.h>
#include <linux/types.h>

struct perf_evsel;
@@ -43,6 +44,11 @@ LIBPERF_API int perf_evsel__refresh_cpu(struct perf_evsel *evsel, int refresh,
int cpu_map_idx);
LIBPERF_API int perf_evsel__period(struct perf_evsel *evsel, __u64 period);
LIBPERF_API int perf_evsel__period_cpu(struct perf_evsel *evsel, __u64 period, int cpu_map_idx);
+LIBPERF_API int perf_evsel__set_signal(struct perf_evsel *evsel, int owner_type,
+ unsigned int signal, struct sigaction *sig);
+LIBPERF_API int perf_evsel__set_signal_cpu(struct perf_evsel *evsel, int owner_type,
+ unsigned int signal, struct sigaction *sig,
+ int cpu_map_idx);
LIBPERF_API struct perf_cpu_map *perf_evsel__cpus(struct perf_evsel *evsel);
LIBPERF_API struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel);
LIBPERF_API struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
index 83ecbce9cfbb..5e04fe2b611c 100644
--- a/tools/lib/perf/libperf.map
+++ b/tools/lib/perf/libperf.map
@@ -32,6 +32,8 @@ LIBPERF_0.0.1 {
perf_evsel__refresh_cpu;
perf_evsel__period;
perf_evsel__period_cpu;
+ perf_evsel__set_signal;
+ perf_evsel__set_signal_cpu;
perf_evsel__cpus;
perf_evsel__threads;
perf_evsel__attr;
--
2.31.1

2022-02-25 17:20:18

by [email protected]

[permalink] [raw]
Subject: [RFC PATCH 3/7] libperf: Add perf_evsel__refresh()/period() functions

From: Shunsuke Nakamura <[email protected]>

Add the following functions:

perf_evsel__refresh()
perf_evsel__refresh_cpu()
perf_evsel__period()
perf_evsel__period_cpu()

to set the over flow limit and period.

Signed-off-by: Shunsuke Nakamura <[email protected]>
---
tools/lib/perf/Documentation/libperf.txt | 5 ++
tools/lib/perf/evsel.c | 68 +++++++++++++++++++++---
tools/lib/perf/include/perf/evsel.h | 5 ++
tools/lib/perf/libperf.map | 4 ++
4 files changed, 76 insertions(+), 6 deletions(-)

diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
index 96a451cd34eb..8f523293fb9d 100644
--- a/tools/lib/perf/Documentation/libperf.txt
+++ b/tools/lib/perf/Documentation/libperf.txt
@@ -146,6 +146,11 @@ SYNOPSIS
int perf_evsel__enable_cpu(struct perf_evsel *evsel, int cpu_map_idx);
int perf_evsel__disable(struct perf_evsel *evsel);
int perf_evsel__disable_cpu(struct perf_evsel *evsel, int cpu_map_idx);
+ int perf_evsel__refresh(struct perf_evsel *evsel, int refresh);
+ int perf_evsel__refresh_cpu(struct perf_evsel *evsel, int refresh,
+ int cpu_map_idx);
+ int perf_evsel__period(struct perf_evsel *evsel, int period);
+ int perf_evsel__period_cpu(struct perf_evsel *evsel, int period, int cpu_map_idx);
struct perf_cpu_map *perf_evsel__cpus(struct perf_evsel *evsel);
struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel);
struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index d22b1468a1ad..8348545874e4 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -330,7 +330,7 @@ int perf_evsel__read(struct perf_evsel *evsel, int cpu_map_idx, int thread,
}

static int perf_evsel__run_ioctl(struct perf_evsel *evsel,
- int ioc, void *arg,
+ int ioc, unsigned long arg,
int cpu_map_idx)
{
int thread;
@@ -353,7 +353,7 @@ static int perf_evsel__run_ioctl(struct perf_evsel *evsel,

int perf_evsel__enable_cpu(struct perf_evsel *evsel, int cpu_map_idx)
{
- return perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_ENABLE, NULL, cpu_map_idx);
+ return perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_ENABLE, 0, cpu_map_idx);
}

int perf_evsel__enable(struct perf_evsel *evsel)
@@ -362,13 +362,13 @@ int perf_evsel__enable(struct perf_evsel *evsel)
int err = 0;

for (i = 0; i < xyarray__max_x(evsel->fd) && !err; i++)
- err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_ENABLE, NULL, i);
+ err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_ENABLE, 0, i);
return err;
}

int perf_evsel__disable_cpu(struct perf_evsel *evsel, int cpu_map_idx)
{
- return perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_DISABLE, NULL, cpu_map_idx);
+ return perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_DISABLE, 0, cpu_map_idx);
}

int perf_evsel__disable(struct perf_evsel *evsel)
@@ -377,7 +377,63 @@ int perf_evsel__disable(struct perf_evsel *evsel)
int err = 0;

for (i = 0; i < xyarray__max_x(evsel->fd) && !err; i++)
- err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_DISABLE, NULL, i);
+ err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_DISABLE, 0, i);
+ return err;
+}
+
+int perf_evsel__refresh_cpu(struct perf_evsel *evsel, int refresh, int cpu_map_idx)
+{
+ return perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_REFRESH, refresh, cpu_map_idx);
+}
+
+int perf_evsel__refresh(struct perf_evsel *evsel, int refresh)
+{
+ int i;
+ int err = 0;
+
+ for (i = 0; i < xyarray__max_x(evsel->fd) && !err; i++)
+ err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_REFRESH, refresh, i);
+ return err;
+}
+
+int perf_evsel__period_cpu(struct perf_evsel *evsel, __u64 period, int cpu_map_idx)
+{
+ int err = 0;
+ struct perf_event_attr *attr;
+
+ err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_PERIOD,
+ (unsigned long)&period, cpu_map_idx);
+ if (err)
+ return err;
+
+ attr = perf_evsel__attr(evsel);
+ if (!attr)
+ return -1;
+
+ attr->sample_period = period;
+
+ return err;
+}
+
+int perf_evsel__period(struct perf_evsel *evsel, __u64 period)
+{
+ int i;
+ int err = 0;
+ struct perf_event_attr *attr;
+
+ for (i = 0; i < xyarray__max_x(evsel->fd) && !err; i++) {
+ err = perf_evsel__run_ioctl(evsel, PERF_EVENT_IOC_PERIOD,
+ (unsigned long)&period, i);
+ if (err)
+ return err;
+ }
+
+ attr = perf_evsel__attr(evsel);
+ if (!attr)
+ return -1;
+
+ attr->sample_period = period;
+
return err;
}

@@ -388,7 +444,7 @@ int perf_evsel__apply_filter(struct perf_evsel *evsel, const char *filter)
for (i = 0; i < perf_cpu_map__nr(evsel->cpus) && !err; i++)
err = perf_evsel__run_ioctl(evsel,
PERF_EVENT_IOC_SET_FILTER,
- (void *)filter, i);
+ (unsigned long)filter, i);
return err;
}

diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h
index 23b0334a4c57..9ec24a5f5f9f 100644
--- a/tools/lib/perf/include/perf/evsel.h
+++ b/tools/lib/perf/include/perf/evsel.h
@@ -38,6 +38,11 @@ LIBPERF_API int perf_evsel__enable(struct perf_evsel *evsel);
LIBPERF_API int perf_evsel__enable_cpu(struct perf_evsel *evsel, int cpu_map_idx);
LIBPERF_API int perf_evsel__disable(struct perf_evsel *evsel);
LIBPERF_API int perf_evsel__disable_cpu(struct perf_evsel *evsel, int cpu_map_idx);
+LIBPERF_API int perf_evsel__refresh(struct perf_evsel *evsel, int refresh);
+LIBPERF_API int perf_evsel__refresh_cpu(struct perf_evsel *evsel, int refresh,
+ int cpu_map_idx);
+LIBPERF_API int perf_evsel__period(struct perf_evsel *evsel, __u64 period);
+LIBPERF_API int perf_evsel__period_cpu(struct perf_evsel *evsel, __u64 period, int cpu_map_idx);
LIBPERF_API struct perf_cpu_map *perf_evsel__cpus(struct perf_evsel *evsel);
LIBPERF_API struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel);
LIBPERF_API struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
index 0f8d13f9009b..83ecbce9cfbb 100644
--- a/tools/lib/perf/libperf.map
+++ b/tools/lib/perf/libperf.map
@@ -28,6 +28,10 @@ LIBPERF_0.0.1 {
perf_evsel__munmap;
perf_evsel__mmap_base;
perf_evsel__read;
+ perf_evsel__refresh;
+ perf_evsel__refresh_cpu;
+ perf_evsel__period;
+ perf_evsel__period_cpu;
perf_evsel__cpus;
perf_evsel__threads;
perf_evsel__attr;
--
2.31.1

2022-02-26 01:10:11

by [email protected]

[permalink] [raw]
Subject: [RFC PATCH 7/7] libperf test: Add test_detect_overflow_event()

From: Shunsuke Nakamura <[email protected]>

Add a test to detect overflowed events.

Committer testing:

$ sudo make tests -C tools/lib/perf/ V=1
make: Entering directory '/home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/lib/perf'
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=. obj=libperf
make -C /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/lib/api/ O= libapi.a
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=./fd obj=libapi
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=./fs obj=libapi
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=. obj=tests
make -f /home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/build/Makefile.build dir=./tests obj=tests
running static:
- running tests/test-cpumap.c...OK
- running tests/test-threadmap.c...OK
- running tests/test-evlist.c...

<SNIP>

Event 0 -- overflow flag = 0x1, POLL_UP = 1, other signal event = 0
Event 1 -- overflow flag = 0x2, POLL_UP = 1, other signal event = 0
Event 2 -- overflow flag = 0x4, POLL_UP = 1, other signal event = 0
Event 3 -- overflow flag = 0x8, POLL_UP = 1, other signal event = 0
OK
- running tests/test-evsel.c...

<SNIP>

OK
running dynamic:
- running tests/test-cpumap.c...OK
- running tests/test-threadmap.c...OK
- running tests/test-evlist.c...

<SNIP>

Event 0 -- overflow flag = 0x1, POLL_UP = 1, other signal event = 0
Event 1 -- overflow flag = 0x2, POLL_UP = 1, other signal event = 0
Event 2 -- overflow flag = 0x4, POLL_UP = 1, other signal event = 0
Event 3 -- overflow flag = 0x8, POLL_UP = 1, other signal event = 0
OK
- running tests/test-evsel.c...

<SNIP>

OK
make: Leaving directory '/home/nakamura/build_work/build_kernel/linux-kernel/linux/tools/lib/perf'

Signed-off-by: Shunsuke Nakamura <[email protected]>
---
tools/lib/perf/tests/test-evlist.c | 119 +++++++++++++++++++++++++++++
1 file changed, 119 insertions(+)

diff --git a/tools/lib/perf/tests/test-evlist.c b/tools/lib/perf/tests/test-evlist.c
index fafc6b0f8687..c0f0109c8b51 100644
--- a/tools/lib/perf/tests/test-evlist.c
+++ b/tools/lib/perf/tests/test-evlist.c
@@ -5,6 +5,8 @@
#include <stdarg.h>
#include <unistd.h>
#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
#include <linux/perf_event.h>
#include <linux/limits.h>
#include <sys/types.h>
@@ -24,6 +26,13 @@
#define EVENT_NUM 15
#define WAIT_COUNT 100000000UL

+static unsigned int overflow_flag;
+static struct signal_counts {
+ int hup;
+ int others;
+} sig_count = { 0, 0 };
+static struct perf_evlist *s_evlist;
+
static int libperf_print(enum libperf_print_level level,
const char *fmt, va_list ap)
{
@@ -570,6 +579,115 @@ static int test_stat_multiplexing(void)
return 0;
}

+static void sig_handler(int signo, siginfo_t *info, void *uc)
+{
+ int err;
+ int idx = 0;
+ struct perf_evsel *evsel;
+
+ switch (info->si_code) {
+ case POLL_HUP:
+ perf_evlist__for_each_evsel(s_evlist, evsel) {
+ err = perf_evsel__check_fd(evsel, info->si_fd);
+ if (!err) {
+ overflow_flag = (1U << idx);
+ sig_count.hup++;
+ break;
+ }
+ idx++;
+ }
+ break;
+ default:
+ perf_evlist__for_each_evsel(s_evlist, evsel) {
+ err = perf_evsel__check_fd(evsel, info->si_fd);
+ if (!err) {
+ overflow_flag = (1U << idx);
+ sig_count.others++;
+ break;
+ }
+ idx++;
+ }
+ }
+}
+
+static int test_stat_overflow_event(void)
+{
+ static struct sigaction sig;
+
+ struct perf_thread_map *threads;
+ struct perf_evsel *evsel;
+ struct perf_event_attr attr = {
+ .type = PERF_TYPE_SOFTWARE,
+ .config = PERF_COUNT_SW_CPU_CLOCK,
+ .sample_type = PERF_SAMPLE_PERIOD,
+ .sample_period = 100000,
+ .disabled = 1,
+ };
+ int err, i, event_num = 4;
+ unsigned int wait_count;
+
+ /* setup signal handler */
+ memset(&sig, 0, sizeof(struct sigaction));
+ sig.sa_sigaction = (void *)sig_handler;
+ sig.sa_flags = SA_SIGINFO;
+
+ threads = perf_thread_map__new_dummy();
+ __T("failed to create threads", threads);
+
+ perf_thread_map__set_pid(threads, 0, 0);
+
+ s_evlist = perf_evlist__new();
+ __T("failed to create evlist", s_evlist);
+
+ for (i = 0; i < event_num; i++) {
+ evsel = perf_evsel__new(&attr);
+ __T("failed to create evsel", evsel);
+
+ err = perf_evsel__set_close_on_exec(evsel);
+ __T("failed to set PERF_FLAG_FD_CLOEXEC flag to evsel", err == 0);
+
+ perf_evlist__add(s_evlist, evsel);
+ }
+
+ perf_evlist__set_maps(s_evlist, NULL, threads);
+
+ err = perf_evlist__open(s_evlist);
+ __T("failed to open evlist", err == 0);
+
+ i = 0;
+ perf_evlist__for_each_evsel(s_evlist, evsel) {
+ err = perf_evsel__set_signal(evsel, F_OWNER_PID, SIGIO, &sig);
+ __T("failed to set signal", err == 0);
+
+ err = perf_evsel__refresh(evsel, 1);
+ __T("failed to refresh evsel", err == 0);
+
+ wait_count = WAIT_COUNT;
+ while (wait_count--)
+ ;
+
+ __T_VERBOSE("Event %2d -- overflow flag = %#x, ",
+ i, overflow_flag);
+ __T_VERBOSE("POLL_UP = %d, other signal event = %d\n",
+ sig_count.hup, sig_count.others);
+
+ __T("unexpected event overflow detected", overflow_flag && (1U << i));
+ __T("unexpected signal event detected",
+ sig_count.hup == 1 && sig_count.others == 0);
+
+ overflow_flag = 0;
+ sig_count.hup = 0;
+ sig_count.others = 0;
+ i++;
+ }
+
+ perf_evlist__close(s_evlist);
+ perf_evlist__delete(s_evlist);
+ perf_thread_map__put(threads);
+
+ return 0;
+}
+
int test_evlist(int argc, char **argv)
{
__T_START;
@@ -582,6 +700,7 @@ int test_evlist(int argc, char **argv)
test_mmap_thread();
test_mmap_cpus();
test_stat_multiplexing();
+ test_stat_overflow_event();

__T_END;
return tests_failed == 0 ? 0 : -1;
--
2.31.1

2022-02-26 18:42:20

by Jiri Olsa

[permalink] [raw]
Subject: Re: [RFC PATCH 0/7] libperf: Add overflow detection of sampling events

On Fri, Feb 25, 2022 at 07:31:07PM +0900, Shunsuke wrote:
> From: Shunsuke Nakamura <[email protected]>
>
> This patch series adds sampling event overflow detection capability
> to libperf.
>
> First patch fixes a typo in the error message that I noticed.
>
> Second patch adds a interface to set PERF_FLAG_FD_CLOEXEC
>
> Third patch adds a interface to perform IOC_REFRESH and IOC_PERIOD.
>
> Fourth patch adds a interface to set the signal handler.
>
> Fifth patch adds a interface to detect overflowed events.
>
> Sixth and seventh patch adds tests.
>
> Shunsuke Nakamura (7):
> libperf tests: Fix typo in the error message "evsel" -> "evlist"
> libperf: Add perf_evsel__set_close_on_exec() function
> libperf: Add perf_evsel__refresh()/period() functions
> libperf: Add perf_evsel__set_signal() functions
> libperf: Add perf_evsel__check_fd() functions
> libperf test: Add test_stat_overflow()
> libperf test: Add test_detect_overflow_event()

hi,
I think the interface might be more clear if we use additional options
for new and open functions, same way like it's done in libbpf

how about adding following interface:

- perf_evsel__new_opts would allow to setup needed attr fields before opening

struct perf_evsel_new_opts {
/* size of this struct, for forward/backward compatiblity */
size_t sz;

int open_flags;
int sample_period;
}

struct perf_evsel *perf_evsel__new_opts(struct perf_event_attr *attr,
struct perf_evsel_new_opts *opts);

- perf_evlist__open_opts would do additional setup 'after' the event
is open and we have file descriptor available


struct perf_evsel_open_opts {
/* size of this struct, for forward/backward compatiblity */
size_t sz;

int flags; /* fcntl flags */
int signal;
int owner_type;
}

int perf_evlist__open_opts(struct perf_evlist *evlist,
struct perf_evsel_open_opts *opts);)

int perf_evsel__open_opts(struct perf_evsel *evsel,
struct perf_cpu_map *cpus,
struct perf_thread_map *threads,
struct perf_evsel_open_opts *opts)

not sure we want special opts for evlist.. the evlist open
is just a wrapper and I don't think there's special open
info just for evlist

I did not analyze your usecases deeply, so I might be missing some
case where above API would need some adjustment, but from the quick
look this could fit and I think it's better than special functions
for each feature

there are additional macros like DECLARE_LIBBPF_OPTS that allows to
define the opts structures in backward compatible way, we'd need to
'borrow' that as well

thoughts?

thanks,
jirka

2022-03-01 08:51:04

by [email protected]

[permalink] [raw]
Subject: RE: [RFC PATCH 0/7] libperf: Add overflow detection of sampling events

Hi jirka

> On Fri, Feb 25, 2022 at 07:31:07PM +0900, Shunsuke wrote:
> > From: Shunsuke Nakamura <[email protected]>
> >
> > This patch series adds sampling event overflow detection capability to
> > libperf.
> >
> > First patch fixes a typo in the error message that I noticed.
> >
> > Second patch adds a interface to set PERF_FLAG_FD_CLOEXEC
> >
> > Third patch adds a interface to perform IOC_REFRESH and IOC_PERIOD.
> >
> > Fourth patch adds a interface to set the signal handler.
> >
> > Fifth patch adds a interface to detect overflowed events.
> >
> > Sixth and seventh patch adds tests.
> >
> > Shunsuke Nakamura (7):
> > libperf tests: Fix typo in the error message "evsel" -> "evlist"
> > libperf: Add perf_evsel__set_close_on_exec() function
> > libperf: Add perf_evsel__refresh()/period() functions
> > libperf: Add perf_evsel__set_signal() functions
> > libperf: Add perf_evsel__check_fd() functions
> > libperf test: Add test_stat_overflow()
> > libperf test: Add test_detect_overflow_event()
>
> hi,
> I think the interface might be more clear if we use additional options for new and
> open functions, same way like it's done in libbpf
>
> how about adding following interface:
>
> - perf_evsel__new_opts would allow to setup needed attr fields before opening
>
> struct perf_evsel_new_opts {
> /* size of this struct, for forward/backward compatiblity */
> size_t sz;
>
> int open_flags;
> int sample_period;
> }
>
> struct perf_evsel *perf_evsel__new_opts(struct perf_event_attr *attr,
> struct perf_evsel_new_opts
> *opts);
>
> - perf_evlist__open_opts would do additional setup 'after' the event
> is open and we have file descriptor available
>
>
> struct perf_evsel_open_opts {
> /* size of this struct, for forward/backward compatiblity */
> size_t sz;
>
> int flags; /* fcntl flags */
> int signal;
> int owner_type;
> }
>
> int perf_evlist__open_opts(struct perf_evlist *evlist,
> struct perf_evsel_open_opts *opts);)
>
> int perf_evsel__open_opts(struct perf_evsel *evsel,
> struct perf_cpu_map *cpus,
> struct perf_thread_map *threads,
> struct perf_evsel_open_opts *opts)
>
> not sure we want special opts for evlist.. the evlist open
> is just a wrapper and I don't think there's special open
> info just for evlist
>
> I did not analyze your usecases deeply, so I might be missing some case where
> above API would need some adjustment, but from the quick look this could fit and
> I think it's better than special functions for each feature
>
> there are additional macros like DECLARE_LIBBPF_OPTS that allows to define
> the opts structures in backward compatible way, we'd need to 'borrow' that as well
>
> thoughts?

Thank you for your comment. I'll consider about it.

Best Regards
Shunsuke