perf top: Use perf_evsel__open

Now that it handles group_fd and inherit we can use it, sharing it with
stat.

Next step: 'perf record' should use, then move the mmap_array out of
->priv and into perf_evsel, with top and record sharing this, and at the
same time, write a 'perf test' stress test.

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>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 42 insertions, 50 deletions

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 1bc465215fc6..15d89bede2fb 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1210,39 +1210,50 @@ static void perf_session__mmap_read(struct perf_session *self)
         }
 }
 
-int group_fd;
-
 static void start_counter(int i, struct perf_evlist *evlist,
                           struct perf_evsel *evsel)
 {
         struct xyarray *mmap_array = evsel->priv;
         struct mmap_data *mm;
-        struct perf_event_attr *attr;
-        int cpu = -1;
         int thread_index;
 
-        if (target_tid == -1)
-                cpu = cpus->map[i];
-
-        attr = &evsel->attr;
+        for (thread_index = 0; thread_index < threads->nr; thread_index++) {
+                assert(FD(evsel, i, thread_index) >= 0);
+                fcntl(FD(evsel, i, thread_index), F_SETFL, O_NONBLOCK);
 
-        attr->sample_type       = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
+                evlist->pollfd[evlist->nr_fds].fd = FD(evsel, i, thread_index);
+                evlist->pollfd[evlist->nr_fds].events = POLLIN;
+                evlist->nr_fds++;
 
-        if (freq) {
-                attr->sample_type       |= PERF_SAMPLE_PERIOD;
-                attr->freq              = 1;
-                attr->sample_freq       = freq;
+                mm = xyarray__entry(mmap_array, i, thread_index);
+                mm->prev = 0;
+                mm->mask = mmap_pages*page_size - 1;
+                mm->base = mmap(NULL, (mmap_pages+1)*page_size,
+                                PROT_READ, MAP_SHARED, FD(evsel, i, thread_index), 0);
+                if (mm->base == MAP_FAILED)
+                        die("failed to mmap with %d (%s)\n", errno, strerror(errno));
         }
+}
+
+static void start_counters(struct perf_evlist *evlist)
+{
+        struct perf_evsel *counter;
+        int i;
 
-        attr->inherit           = (cpu < 0) && inherit;
-        attr->mmap              = 1;
+        list_for_each_entry(counter, &evlist->entries, node) {
+                struct perf_event_attr *attr = &counter->attr;
 
-        for (thread_index = 0; thread_index < threads->nr; thread_index++) {
-try_again:
-                FD(evsel, i, thread_index) = sys_perf_event_open(attr,
-                                threads->map[thread_index], cpu, group_fd, 0);
+                attr->sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
+
+                if (freq) {
+                        attr->sample_type |= PERF_SAMPLE_PERIOD;
+                        attr->freq        = 1;
+                        attr->sample_freq = freq;
+                }
 
-                if (FD(evsel, i, thread_index) < 0) {
+                attr->mmap = 1;
+try_again:
+                if (perf_evsel__open(counter, cpus, threads, group, inherit) < 0) {
                         int err = errno;
 
                         if (err == EPERM || err == EACCES)
@@ -1254,8 +1265,8 @@ try_again:
                          * based cpu-clock-tick sw counter, which
                          * is always available even if no PMU support:
                          */
-                        if (attr->type == PERF_TYPE_HARDWARE
-                                        && attr->config == PERF_COUNT_HW_CPU_CYCLES) {
+                        if (attr->type == PERF_TYPE_HARDWARE &&
+                            attr->config == PERF_COUNT_HW_CPU_CYCLES) {
 
                                 if (verbose)
                                         warning(" ... trying to fall back to cpu-clock-ticks\n");
@@ -1265,39 +1276,24 @@ try_again:
                                 goto try_again;
                         }
                         printf("\n");
-                        error("sys_perf_event_open() syscall returned with %d (%s).  /bin/dmesg may provide additional information.\n",
-                                        FD(evsel, i, thread_index), strerror(err));
+                        error("sys_perf_event_open() syscall returned with %d "
+                              "(%s).  /bin/dmesg may provide additional information.\n",
+                              err, strerror(err));
                         die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");
                         exit(-1);
                 }
-                assert(FD(evsel, i, thread_index) >= 0);
-                fcntl(FD(evsel, i, thread_index), F_SETFL, O_NONBLOCK);
-
-                /*
-                 * First counter acts as the group leader:
-                 */
-                if (group && group_fd == -1)
-                        group_fd = FD(evsel, i, thread_index);
-
-                evlist->pollfd[evlist->nr_fds].fd = FD(evsel, i, thread_index);
-                evlist->pollfd[evlist->nr_fds].events = POLLIN;
-                evlist->nr_fds++;
+        }
 
-                mm = xyarray__entry(mmap_array, i, thread_index);
-                mm->prev = 0;
-                mm->mask = mmap_pages*page_size - 1;
-                mm->base = mmap(NULL, (mmap_pages+1)*page_size,
-                                PROT_READ, MAP_SHARED, FD(evsel, i, thread_index), 0);
-                if (mm->base == MAP_FAILED)
-                        die("failed to mmap with %d (%s)\n", errno, strerror(errno));
+        for (i = 0; i < cpus->nr; i++) {
+                list_for_each_entry(counter, &evlist->entries, node)
+                        start_counter(i, evsel_list, counter);
         }
 }
 
 static int __cmd_top(void)
 {
         pthread_t thread;
-        struct perf_evsel *counter;
-        int i, ret;
+        int ret;
         /*
          * FIXME: perf_session__new should allow passing a O_MMAP, so that all this
          * mmap reading, etc is encapsulated in it. Use O_WRONLY for now.
@@ -1311,11 +1307,7 @@ static int __cmd_top(void)
         else
                 event__synthesize_threads(event__process, session);
 
-        for (i = 0; i < cpus->nr; i++) {
-                group_fd = -1;
-                list_for_each_entry(counter, &evsel_list->entries, node)
-                        start_counter(i, evsel_list, counter);
-        }
+        start_counters(evsel_list);
 
         /* Wait for a minimal set of events before starting the snapshot */
         poll(evsel_list->pollfd, evsel_list->nr_fds, 100);