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>

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 1bc4652..15d89be 100644 (file)
--- 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);