4 files changed, 72 insertions, 35 deletions

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 74d7481ed7a..ab7f667de1b 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -17,6 +17,9 @@ captured via perf record.
 
 If no parameters are passed it will assume perf.data.old and perf.data.
 
+The differential profile is displayed only for events matching both
+specified perf.data files.
+
 OPTIONS
 -------
 -M::
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index d29d350fb2b..e9933fdd256 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -10,6 +10,7 @@
 #include "util/event.h"
 #include "util/hist.h"
 #include "util/evsel.h"
+#include "util/evlist.h"
 #include "util/session.h"
 #include "util/tool.h"
 #include "util/sort.h"
@@ -24,11 +25,6 @@ static char	  diff__default_sort_order[] = "dso,symbol";
 static bool  force;
 static bool show_displacement;
 
-struct perf_diff {
-        struct perf_tool tool;
-        struct perf_session *session;
-};
-
 static int hists__add_entry(struct hists *self,
                             struct addr_location *al, u64 period)
 {
@@ -37,14 +33,12 @@ static int hists__add_entry(struct hists *self,
         return -ENOMEM;
 }
 
-static int diff__process_sample_event(struct perf_tool *tool,
+static int diff__process_sample_event(struct perf_tool *tool __used,
                                       union perf_event *event,
                                       struct perf_sample *sample,
-                                      struct perf_evsel *evsel __used,
+                                      struct perf_evsel *evsel,
                                       struct machine *machine)
 {
-        struct perf_diff *_diff = container_of(tool, struct perf_diff, tool);
-        struct perf_session *session = _diff->session;
         struct addr_location al;
 
         if (perf_event__preprocess_sample(event, machine, &al, sample, NULL) < 0) {
@@ -56,26 +50,24 @@ static int diff__process_sample_event(struct perf_tool *tool,
         if (al.filtered || al.sym == NULL)
                 return 0;
 
-        if (hists__add_entry(&session->hists, &al, sample->period)) {
+        if (hists__add_entry(&evsel->hists, &al, sample->period)) {
                 pr_warning("problem incrementing symbol period, skipping event\n");
                 return -1;
         }
 
-        session->hists.stats.total_period += sample->period;
+        evsel->hists.stats.total_period += sample->period;
         return 0;
 }
 
-static struct perf_diff diff = {
-        .tool = {
-                .sample = diff__process_sample_event,
-                .mmap   = perf_event__process_mmap,
-                .comm   = perf_event__process_comm,
-                .exit   = perf_event__process_task,
-                .fork   = perf_event__process_task,
-                .lost   = perf_event__process_lost,
-                .ordered_samples = true,
-                .ordering_requires_timestamps = true,
-        },
+static struct perf_tool tool = {
+        .sample = diff__process_sample_event,
+        .mmap   = perf_event__process_mmap,
+        .comm   = perf_event__process_comm,
+        .exit   = perf_event__process_task,
+        .fork   = perf_event__process_task,
+        .lost   = perf_event__process_lost,
+        .ordered_samples = true,
+        .ordering_requires_timestamps = true,
 };
 
 static void perf_session__insert_hist_entry_by_name(struct rb_root *root,
@@ -146,34 +138,71 @@ static void hists__match(struct hists *older, struct hists *newer)
         }
 }
 
+static struct perf_evsel *evsel_match(struct perf_evsel *evsel,
+                                      struct perf_evlist *evlist)
+{
+        struct perf_evsel *e;
+
+        list_for_each_entry(e, &evlist->entries, node)
+                if (perf_evsel__match2(evsel, e))
+                        return e;
+
+        return NULL;
+}
+
 static int __cmd_diff(void)
 {
         int ret, i;
 #define older (session[0])
 #define newer (session[1])
         struct perf_session *session[2];
+        struct perf_evlist *evlist_new, *evlist_old;
+        struct perf_evsel *evsel;
+        bool first = true;
 
         older = perf_session__new(input_old, O_RDONLY, force, false,
-                                  &diff.tool);
+                                  &tool);
         newer = perf_session__new(input_new, O_RDONLY, force, false,
-                                  &diff.tool);
+                                  &tool);
         if (session[0] == NULL || session[1] == NULL)
                 return -ENOMEM;
 
         for (i = 0; i < 2; ++i) {
-                diff.session = session[i];
-                ret = perf_session__process_events(session[i], &diff.tool);
+                ret = perf_session__process_events(session[i], &tool);
                 if (ret)
                         goto out_delete;
-                hists__output_resort(&session[i]->hists);
         }
 
-        if (show_displacement)
-                hists__resort_entries(&older->hists);
+        evlist_old = older->evlist;
+        evlist_new = newer->evlist;
+
+        list_for_each_entry(evsel, &evlist_new->entries, node)
+                hists__output_resort(&evsel->hists);
+
+        list_for_each_entry(evsel, &evlist_old->entries, node) {
+                hists__output_resort(&evsel->hists);
+
+                if (show_displacement)
+                        hists__resort_entries(&evsel->hists);
+        }
+
+        list_for_each_entry(evsel, &evlist_new->entries, node) {
+                struct perf_evsel *evsel_old;
+
+                evsel_old = evsel_match(evsel, evlist_old);
+                if (!evsel_old)
+                        continue;
+
+                fprintf(stdout, "%s# Event '%s'\n#\n", first ? "" : "\n",
+                        perf_evsel__name(evsel));
+
+                first = false;
+
+                hists__match(&evsel_old->hists, &evsel->hists);
+                hists__fprintf(&evsel->hists, &evsel_old->hists,
+                               show_displacement, true, 0, 0, stdout);
+        }
 
-        hists__match(&older->hists, &newer->hists);
-        hists__fprintf(&newer->hists, &older->hists,
-                       show_displacement, true, 0, 0, stdout);
 out_delete:
         for (i = 0; i < 2; ++i)
                 perf_session__delete(session[i]);
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index a3f562cec43..390690eb878 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -124,6 +124,13 @@ void perf_evsel__close(struct perf_evsel *evsel, int ncpus, int nthreads);
         (evsel->attr.type == PERF_TYPE_##t &&   \
          evsel->attr.config == PERF_COUNT_##c)
 
+static inline bool perf_evsel__match2(struct perf_evsel *e1,
+                                      struct perf_evsel *e2)
+{
+        return (e1->attr.type == e2->attr.type) &&
+               (e1->attr.config == e2->attr.config);
+}
+
 int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
                               int cpu, int thread, bool scale);
 
diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index 176a60902f5..aab414fbb64 100644
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -36,9 +36,7 @@ struct perf_session {
         struct pevent           *pevent;
         /*
          * FIXME: Need to split this up further, we need global
-         *        stats + per event stats. 'perf diff' also needs
-         *        to properly support multiple events in a single
-         *        perf.data file.
+         *        stats + per event stats.
          */
         struct hists            hists;
         int                     fd;