keep-tracking.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <unistd.h>
#include <sys/prctl.h>
#include "parse-events.h"
#include "evlist.h"
#include "evsel.h"
#include "thread_map.h"
#include "cpumap.h"
#include "tests.h"
#define CHECK__(x) { \
while ((x) < 0) { \
pr_debug(#x " failed!\n"); \
goto out_err; \
} \
}
#define CHECK_NOT_NULL__(x) { \
while ((x) == NULL) { \
pr_debug(#x " failed!\n"); \
goto out_err; \
} \
}
static int find_comm(struct perf_evlist *evlist, const char *comm)
{
union perf_event *event;
int i, found;
found = 0;
for (i = 0; i < evlist->nr_mmaps; i++) {
while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
if (event->header.type == PERF_RECORD_COMM &&
(pid_t)event->comm.pid == getpid() &&
(pid_t)event->comm.tid == getpid() &&
strcmp(event->comm.comm, comm) == 0)
found += 1;
perf_evlist__mmap_consume(evlist, i);
}
}
return found;
}
/**
* test__keep_tracking - test using a dummy software event to keep tracking.
*
* This function implements a test that checks that tracking events continue
* when an event is disabled but a dummy software event is not disabled. If the
* test passes %0 is returned, otherwise %-1 is returned.
*/
int test__keep_tracking(struct test *test __maybe_unused, int subtest __maybe_unused)
{
struct record_opts opts = {
.mmap_pages = UINT_MAX,
.user_freq = UINT_MAX,
.user_interval = ULLONG_MAX,
.target = {
.uses_mmap = true,
},
};
struct thread_map *threads = NULL;
struct cpu_map *cpus = NULL;
struct perf_evlist *evlist = NULL;
struct perf_evsel *evsel = NULL;
int found, err = -1;
const char *comm;
threads = thread_map__new(-1, getpid(), UINT_MAX);
CHECK_NOT_NULL__(threads);
cpus = cpu_map__new(NULL);
CHECK_NOT_NULL__(cpus);
evlist = perf_evlist__new();
CHECK_NOT_NULL__(evlist);
perf_evlist__set_maps(evlist, cpus, threads);
CHECK__(parse_events(evlist, "dummy:u", NULL));
CHECK__(parse_events(evlist, "cycles:u", NULL));
perf_evlist__config(evlist, &opts, NULL);
evsel = perf_evlist__first(evlist);
evsel->attr.comm = 1;
evsel->attr.disabled = 1;
evsel->attr.enable_on_exec = 0;
if (perf_evlist__open(evlist) < 0) {
pr_debug("Unable to open dummy and cycles event\n");
err = TEST_SKIP;
goto out_err;
}
CHECK__(perf_evlist__mmap(evlist, UINT_MAX, false));
/*
* First, test that a 'comm' event can be found when the event is
* enabled.
*/
perf_evlist__enable(evlist);
comm = "Test COMM 1";
CHECK__(prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0));
perf_evlist__disable(evlist);
found = find_comm(evlist, comm);
if (found != 1) {
pr_debug("First time, failed to find tracking event.\n");
goto out_err;
}
/*
* Secondly, test that a 'comm' event can be found when the event is
* disabled with the dummy event still enabled.
*/
perf_evlist__enable(evlist);
evsel = perf_evlist__last(evlist);
CHECK__(perf_evsel__disable(evsel));
comm = "Test COMM 2";
CHECK__(prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0));
perf_evlist__disable(evlist);
found = find_comm(evlist, comm);
if (found != 1) {
pr_debug("Seconf time, failed to find tracking event.\n");
goto out_err;
}
err = 0;
out_err:
if (evlist) {
perf_evlist__disable(evlist);
perf_evlist__delete(evlist);
} else {
cpu_map__put(cpus);
thread_map__put(threads);
}
return err;
}