[tip:perf/urgent] perf evsel: Support perf_evsel__open(cpus > 1 && threads > 1)

tip-bot for Arnaldo Carvalho de Melo
2011-01-11T11:12:03Z

Commit-ID: 0252208eb52f6fe8731a47804eddc7ba93f60a87
Gitweb: http://git.kernel.org/tip/0252208eb52f6fe8731a47804eddc7ba93f60a87
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Tue, 4 Jan 2011 11:55:27 -0200
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 10 Jan 2011 22:03:26 -0200

perf evsel: Support perf_evsel__open(cpus > 1 && threads > 1)

And a test for it:

[acme@felicio linux]$ perf test
1: vmlinux symtab matches kallsyms: Ok
2: detect open syscall event: Ok
3: detect open syscall event on all cpus: Ok
[acme@felicio linux]$

Translating C the test does:

1. generates different number of open syscalls on each CPU
by using sched_setaffinity
2. Verifies that the expected number of events is generated
on each CPU

It works as expected.

LKML-Reference: <new-submission>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-test.c | 110 +++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/evsel.c | 82 ++++++++++++++++++++-------------
2 files changed, 159 insertions(+), 33 deletions(-)

diff --git a/tools/perf/builtin-test.c b/tools/perf/builtin-test.c
index e12753f..ed56961 100644
--- a/tools/perf/builtin-test.c
+++ b/tools/perf/builtin-test.c
@@ -234,6 +234,7 @@ out:
return err;
}

+#include "util/cpumap.h"
#include "util/evsel.h"
#include <sys/types.h>

@@ -321,6 +322,111 @@ out_thread_map_delete:
return err;
}

+#include <sched.h>
+
+static int test__open_syscall_event_on_all_cpus(void)
+{
+ int err = -1, fd, cpu;
+ struct thread_map *threads;
+ struct cpu_map *cpus;
+ struct perf_evsel *evsel;
+ struct perf_event_attr attr;
+ unsigned int nr_open_calls = 111, i;
+ cpu_set_t *cpu_set;
+ size_t cpu_set_size;
+ int id = trace_event__id("sys_enter_open");
+
+ if (id < 0) {
+ pr_debug("is debugfs mounted on /sys/kernel/debug?\n");
+ return -1;
+ }
+
+ threads = thread_map__new(-1, getpid());
+ if (threads == NULL) {
+ pr_debug("thread_map__new\n");
+ return -1;
+ }
+
+ cpus = cpu_map__new(NULL);
+ if (threads == NULL) {
+ pr_debug("thread_map__new\n");
+ return -1;
+ }
+
+ cpu_set = CPU_ALLOC(cpus->nr);
+
+ if (cpu_set == NULL)
+ goto out_thread_map_delete;
+
+ cpu_set_size = CPU_ALLOC_SIZE(cpus->nr);
+ CPU_ZERO_S(cpu_set_size, cpu_set);
+
+ memset(&attr, 0, sizeof(attr));
+ attr.type = PERF_TYPE_TRACEPOINT;
+ attr.config = id;
+ evsel = perf_evsel__new(&attr, 0);
+ if (evsel == NULL) {
+ pr_debug("perf_evsel__new\n");
+ goto out_cpu_free;
+ }
+
+ if (perf_evsel__open(evsel, cpus, threads) < 0) {
+ pr_debug("failed to open counter: %s, "
+ "tweak /proc/sys/kernel/perf_event_paranoid?\n",
+ strerror(errno));
+ goto out_evsel_delete;
+ }
+
+ for (cpu = 0; cpu < cpus->nr; ++cpu) {
+ unsigned int ncalls = nr_open_calls + cpu;
+
+ CPU_SET(cpu, cpu_set);
+ sched_setaffinity(0, cpu_set_size, cpu_set);
+ for (i = 0; i < ncalls; ++i) {
+ fd = open("/etc/passwd", O_RDONLY);
+ close(fd);
+ }
+ CPU_CLR(cpu, cpu_set);
+ }
+
+ /*
+ * Here we need to explicitely preallocate the counts, as if
+ * we use the auto allocation it will allocate just for 1 cpu,
+ * as we start by cpu 0.
+ */
+ if (perf_evsel__alloc_counts(evsel, cpus->nr) < 0) {
+ pr_debug("perf_evsel__alloc_counts(ncpus=%d)\n", cpus->nr);
+ goto out_close_fd;
+ }
+
+ for (cpu = 0; cpu < cpus->nr; ++cpu) {
+ unsigned int expected;
+
+ if (perf_evsel__read_on_cpu(evsel, cpu, 0) < 0) {
+ pr_debug("perf_evsel__open_read_on_cpu\n");
+ goto out_close_fd;
+ }
+
+ expected = nr_open_calls + cpu;
+ if (evsel->counts->cpu[cpu].val != expected) {
+ pr_debug("perf_evsel__read_on_cpu: expected to intercept %d calls on cpu %d, got %Ld\n",
+ expected, cpu, evsel->counts->cpu[cpu].val);
+ goto out_close_fd;
+ }
+ }
+
+ err = 0;
+out_close_fd:
+ perf_evsel__close_fd(evsel, 1, threads->nr);
+out_evsel_delete:
+ perf_evsel__delete(evsel);
+out_cpu_free:
+ CPU_FREE(cpu_set);
+out_thread_map_delete:
+ thread_map__delete(threads);
+ return err;
+}
+
static struct test {
const char *desc;
int (*func)(void);
@@ -334,6 +440,10 @@ static struct test {
.func = test__open_syscall_event,
},
{
+ .desc = "detect open syscall event on all cpus",
+ .func = test__open_syscall_event_on_all_cpus,
+ },
+ {
.func = NULL,
},
};
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 1a5591d..f5cfed6 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -127,59 +127,75 @@ int __perf_evsel__read(struct perf_evsel *evsel,
return 0;
}

-int perf_evsel__open_per_cpu(struct perf_evsel *evsel, struct cpu_map *cpus)
+static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
+ struct thread_map *threads)
{
- int cpu;
+ int cpu, thread;

- if (evsel->fd == NULL && perf_evsel__alloc_fd(evsel, cpus->nr, 1) < 0)
+ if (evsel->fd == NULL &&
+ perf_evsel__alloc_fd(evsel, cpus->nr, threads->nr) < 0)
return -1;

for (cpu = 0; cpu < cpus->nr; cpu++) {
- FD(evsel, cpu, 0) = sys_perf_event_open(&evsel->attr, -1,
- cpus->map[cpu], -1, 0);
- if (FD(evsel, cpu, 0) < 0)
- goto out_close;
+ for (thread = 0; thread < threads->nr; thread++) {
+ FD(evsel, cpu, thread) = sys_perf_event_open(&evsel->attr,
+ threads->map[thread],
+ cpus->map[cpu], -1, 0);
+ if (FD(evsel, cpu, thread) < 0)
+ goto out_close;
+ }
}

return 0;

out_close:
- while (--cpu >= 0) {
- close(FD(evsel, cpu, 0));
- FD(evsel, cpu, 0) = -1;
- }
+ do {
+ while (--thread >= 0) {
+ close(FD(evsel, cpu, thread));
+ FD(evsel, cpu, thread) = -1;
+ }
+ thread = threads->nr;
+ } while (--cpu >= 0);
return -1;
}

-int perf_evsel__open_per_thread(struct perf_evsel *evsel, struct thread_map *threads)
+static struct {
+ struct cpu_map map;
+ int cpus[1];
+} empty_cpu_map = {
+ .map.nr = 1,
+ .cpus = { -1, },
+};
+
+static struct {
+ struct thread_map map;
+ int threads[1];
+} empty_thread_map = {
+ .map.nr = 1,
+ .threads = { -1, },
+};
+
+int perf_evsel__open(struct perf_evsel *evsel,
+ struct cpu_map *cpus, struct thread_map *threads)
{
- int thread;
-
- if (evsel->fd == NULL && perf_evsel__alloc_fd(evsel, 1, threads->nr))
- return -1;

- for (thread = 0; thread < threads->nr; thread++) {
- FD(evsel, 0, thread) = sys_perf_event_open(&evsel->attr,
- threads->map[thread], -1, -1, 0);
- if (FD(evsel, 0, thread) < 0)
- goto out_close;
+ if (cpus == NULL) {
+ /* Work around old compiler warnings about strict aliasing */
+ cpus = &empty_cpu_map.map;
}

- return 0;
+ if (threads == NULL)
+ threads = &empty_thread_map.map;

-out_close:
- while (--thread >= 0) {
- close(FD(evsel, 0, thread));
- FD(evsel, 0, thread) = -1;
- }
- return -1;
+ return __perf_evsel__open(evsel, cpus, threads);
}

-int perf_evsel__open(struct perf_evsel *evsel,
- struct cpu_map *cpus, struct thread_map *threads)
+int perf_evsel__open_per_cpu(struct perf_evsel *evsel, struct cpu_map *cpus)
{
- if (threads == NULL)
- return perf_evsel__open_per_cpu(evsel, cpus);
+ return __perf_evsel__open(evsel, cpus, &empty_thread_map.map);
+}

- return perf_evsel__open_per_thread(evsel, threads);
+int perf_evsel__open_per_thread(struct perf_evsel *evsel, struct thread_map *threads)
+{
+ return __perf_evsel__open(evsel, &empty_cpu_map.map, threads);
}