2 files changed, 86 insertions, 2 deletions

diff --git a/tools/perf/Documentation/perf-timechart.txt b/tools/perf/Documentation/perf-timechart.txt
index ec6b46c7bca0..df98d1c82688 100644
--- a/tools/perf/Documentation/perf-timechart.txt
+++ b/tools/perf/Documentation/perf-timechart.txt
@@ -64,6 +64,19 @@ TIMECHART OPTIONS
         duration or tasks with given name. If number is given it's interpreted
         as number of nanoseconds. If non-numeric string is given it's
         interpreted as task name.
+--io-skip-eagain::
+        Don't draw EAGAIN IO events.
+--io-min-time=<nsecs>::
+        Draw small events as if they lasted min-time. Useful when you need
+        to see very small and fast IO. It's possible to specify ms or us
+        suffix to specify time in milliseconds or microseconds.
+        Default value is 1ms.
+--io-merge-dist=<nsecs>::
+        Merge events that are merge-dist nanoseconds apart.
+        Reduces number of figures on the SVG and makes it more render-friendly.
+        It's possible to specify ms or us suffix to specify time in
+        milliseconds or microseconds.
+        Default value is 1us.
 
 RECORD OPTIONS
 --------------
diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
index 37bf1eb0755f..04c9c53becad 100644
--- a/tools/perf/builtin-timechart.c
+++ b/tools/perf/builtin-timechart.c
@@ -62,7 +62,10 @@ struct timechart {
                                 topology;
         /* IO related settings */
         u64                     io_events;
-        bool                    io_only;
+        bool                    io_only,
+                                skip_eagain;
+        u64                     min_time,
+                                merge_dist;
 };
 
 struct per_pidcomm;
@@ -761,7 +764,7 @@ static int pid_end_io_sample(struct timechart *tchart, int pid, int type,
 {
         struct per_pid *p = find_create_pid(tchart, pid);
         struct per_pidcomm *c = p->current;
-        struct io_sample *sample;
+        struct io_sample *sample, *prev;
 
         if (!c) {
                 pr_warning("Invalid pidcomm!\n");
@@ -785,6 +788,18 @@ static int pid_end_io_sample(struct timechart *tchart, int pid, int type,
         }
 
         sample->end_time = end;
+        prev = sample->next;
+
+        /* we want to be able to see small and fast transfers, so make them
+         * at least min_time long, but don't overlap them */
+        if (sample->end_time - sample->start_time < tchart->min_time)
+                sample->end_time = sample->start_time + tchart->min_time;
+        if (prev && sample->start_time < prev->end_time) {
+                if (prev->err) /* try to make errors more visible */
+                        sample->start_time = prev->end_time;
+                else
+                        prev->end_time = sample->start_time;
+        }
 
         if (ret < 0) {
                 sample->err = ret;
@@ -799,6 +814,24 @@ static int pid_end_io_sample(struct timechart *tchart, int pid, int type,
                 sample->bytes = ret;
         }
 
+        /* merge two requests to make svg smaller and render-friendly */
+        if (prev &&
+            prev->type == sample->type &&
+            prev->err == sample->err &&
+            prev->fd == sample->fd &&
+            prev->end_time + tchart->merge_dist >= sample->start_time) {
+
+                sample->bytes += prev->bytes;
+                sample->merges += prev->merges + 1;
+
+                sample->start_time = prev->start_time;
+                sample->next = prev->next;
+                free(prev);
+
+                if (!sample->err && sample->bytes > c->max_bytes)
+                        c->max_bytes = sample->bytes;
+        }
+
         tchart->io_events++;
 
         return 0;
@@ -1119,6 +1152,10 @@ static void draw_io_bars(struct timechart *tchart)
                         for (sample = c->io_samples; sample; sample = sample->next) {
                                 double h = (double)sample->bytes / c->max_bytes;
 
+                                if (tchart->skip_eagain &&
+                                    sample->err == -EAGAIN)
+                                        continue;
+
                                 if (sample->err)
                                         h = 1;
 
@@ -1849,6 +1886,30 @@ parse_highlight(const struct option *opt __maybe_unused, const char *arg,
         return 0;
 }
 
+static int
+parse_time(const struct option *opt, const char *arg, int __maybe_unused unset)
+{
+        char unit = 'n';
+        u64 *value = opt->value;
+
+        if (sscanf(arg, "%" PRIu64 "%cs", value, &unit) > 0) {
+                switch (unit) {
+                case 'm':
+                        *value *= 1000000;
+                        break;
+                case 'u':
+                        *value *= 1000;
+                        break;
+                case 'n':
+                        break;
+                default:
+                        return -1;
+                }
+        }
+
+        return 0;
+}
+
 int cmd_timechart(int argc, const char **argv,
                   const char *prefix __maybe_unused)
 {
@@ -1861,6 +1922,8 @@ int cmd_timechart(int argc, const char **argv,
                         .ordered_samples = true,
                 },
                 .proc_num = 15,
+                .min_time = 1000000,
+                .merge_dist = 1000,
         };
         const char *output_name = "output.svg";
         const struct option timechart_options[] = {
@@ -1882,6 +1945,14 @@ int cmd_timechart(int argc, const char **argv,
                     "min. number of tasks to print"),
         OPT_BOOLEAN('t', "topology", &tchart.topology,
                     "sort CPUs according to topology"),
+        OPT_BOOLEAN(0, "io-skip-eagain", &tchart.skip_eagain,
+                    "skip EAGAIN errors"),
+        OPT_CALLBACK(0, "io-min-time", &tchart.min_time, "time",
+                     "all IO faster than min-time will visually appear longer",
+                     parse_time),
+        OPT_CALLBACK(0, "io-merge-dist", &tchart.merge_dist, "time",
+                     "merge events that are merge-dist us apart",
+                     parse_time),
         OPT_END()
         };
         const char * const timechart_usage[] = {