perf top: Allow disabling/enabling events dynamicly

Now it is possible to press CTRL+z at anytime and that will disable the
events being monitored, essentially turning 'top' into 'report', with
pressing CTRL+z again making it enable the events again, returning to
the 'top' behaviour, i.e. dynamic + decaying of older samples.

One may want, for instance, play with:

    -d, --delay <n>       number of seconds to delay between refreshes

and:

    -z, --zero            zero history across updates

Plus CTRL+z to see only the events since last zeroing, etc.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-zq7tnh5462blt2yda0bcxh5b@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 38 insertions, 16 deletions

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 6b987424d015..72d8a7ae5986 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -235,10 +235,13 @@ static void perf_top__show_details(struct perf_top *top)
 
         more = symbol__annotate_printf(symbol, he->ms.map, top->sym_evsel,
                                        0, top->sym_pcnt_filter, top->print_entries, 4);
-        if (top->zero)
-                symbol__annotate_zero_histogram(symbol, top->sym_evsel->idx);
-        else
-                symbol__annotate_decay_histogram(symbol, top->sym_evsel->idx);
+
+        if (top->evlist->enabled) {
+                if (top->zero)
+                        symbol__annotate_zero_histogram(symbol, top->sym_evsel->idx);
+                else
+                        symbol__annotate_decay_histogram(symbol, top->sym_evsel->idx);
+        }
         if (more != 0)
                 printf("%d lines not displayed, maybe increase display entries [e]\n", more);
 out_unlock:
@@ -276,11 +279,13 @@ static void perf_top__print_sym_table(struct perf_top *top)
                 return;
         }
 
-        if (top->zero) {
-                hists__delete_entries(hists);
-        } else {
-                hists__decay_entries(hists, top->hide_user_symbols,
-                                     top->hide_kernel_symbols);
+        if (top->evlist->enabled) {
+                if (top->zero) {
+                        hists__delete_entries(hists);
+                } else {
+                        hists__decay_entries(hists, top->hide_user_symbols,
+                                             top->hide_kernel_symbols);
+                }
         }
 
         hists__collapse_resort(hists, NULL);
@@ -545,11 +550,13 @@ static void perf_top__sort_new_samples(void *arg)
 
         hists = evsel__hists(t->sym_evsel);
 
-        if (t->zero) {
-                hists__delete_entries(hists);
-        } else {
-                hists__decay_entries(hists, t->hide_user_symbols,
-                                     t->hide_kernel_symbols);
+        if (t->evlist->enabled) {
+                if (t->zero) {
+                        hists__delete_entries(hists);
+                } else {
+                        hists__decay_entries(hists, t->hide_user_symbols,
+                                             t->hide_kernel_symbols);
+                }
         }
 
         hists__collapse_resort(hists, NULL);
@@ -579,8 +586,21 @@ static void *display_thread_tui(void *arg)
                 hists->uid_filter_str = top->record_opts.target.uid_str;
         }
 
-        perf_evlist__tui_browse_hists(top->evlist, help, &hbt, top->min_percent,
-                                      &top->session->header.env);
+        while (true)  {
+                int key = perf_evlist__tui_browse_hists(top->evlist, help, &hbt,
+                                                        top->min_percent,
+                                                        &top->session->header.env);
+
+                if (key != CTRL('z'))
+                        break;
+
+                perf_evlist__toggle_enable(top->evlist);
+                /*
+                 * No need to refresh, resort/decay histogram entries
+                 * if we are not collecting samples:
+                 */
+                hbt.refresh = top->evlist->enabled ? top->delay_secs : 0;
+        }
 
         done = 1;
         return NULL;
diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index e64893f2fd7f..8f7c4d49d327 100644
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -1736,6 +1736,7 @@ static int perf_evsel__hists_browse(struct perf_evsel *evsel, int nr_events,
         "t             Zoom into current Thread\n"
         "V             Verbose (DSO names in callchains, etc)\n"
         "z             Toggle zeroing of samples\n"
+        "CTRL+z        Enable/Disable events\n"
         "/             Filter symbol by name";
 
         if (browser == NULL)
@@ -1900,6 +1901,7 @@ static int perf_evsel__hists_browse(struct perf_evsel *evsel, int nr_events,
                         /* Fall thru */
                 case 'q':
                 case CTRL('c'):
+                case CTRL('z'):
                         goto out_free_stack;
                 default:
                         continue;