perf diff: Fix to work with new hists design

The perf diff command is broken since:
  perf hists: Threaded addition and sorting of entries
  commit 1980c2ebd7020d82c024b8c4046849b38e78e7da

Several places were broken:
  - hists data need to be collected into opened sessions instead
    of into events
  - session's hists data need to be initialized properly when the
    session is created
  - hist_entry__pcnt_snprintf: the percentage and displacement
    buffer preparation must not use 'ret' because it's used
    as a pointer to the final buffer

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120322133726.GB1601@m.brq.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

5 files changed, 43 insertions, 30 deletions

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 4f19513d7dda..d29d350fb2b7 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -24,6 +24,11 @@ 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)
 {
@@ -32,12 +37,14 @@ static int hists__add_entry(struct hists *self,
         return -ENOMEM;
 }
 
-static int diff__process_sample_event(struct perf_tool *tool __used,
+static int diff__process_sample_event(struct perf_tool *tool,
                                       union perf_event *event,
                                       struct perf_sample *sample,
                                       struct perf_evsel *evsel __used,
                                       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) {
@@ -49,24 +56,26 @@ static int diff__process_sample_event(struct perf_tool *tool __used,
         if (al.filtered || al.sym == NULL)
                 return 0;
 
-        if (hists__add_entry(&evsel->hists, &al, sample->period)) {
+        if (hists__add_entry(&session->hists, &al, sample->period)) {
                 pr_warning("problem incrementing symbol period, skipping event\n");
                 return -1;
         }
 
-        evsel->hists.stats.total_period += sample->period;
+        session->hists.stats.total_period += sample->period;
         return 0;
 }
 
-static struct perf_tool perf_diff = {
-        .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_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 void perf_session__insert_hist_entry_by_name(struct rb_root *root,
@@ -107,12 +116,6 @@ static void hists__resort_entries(struct hists *self)
         self->entries = tmp;
 }
 
-static void hists__set_positions(struct hists *self)
-{
-        hists__output_resort(self);
-        hists__resort_entries(self);
-}
-
 static struct hist_entry *hists__find_entry(struct hists *self,
                                             struct hist_entry *he)
 {
@@ -146,30 +149,37 @@ static void hists__match(struct hists *older, struct hists *newer)
 static int __cmd_diff(void)
 {
         int ret, i;
+#define older (session[0])
+#define newer (session[1])
         struct perf_session *session[2];
 
-        session[0] = perf_session__new(input_old, O_RDONLY, force, false, &perf_diff);
-        session[1] = perf_session__new(input_new, O_RDONLY, force, false, &perf_diff);
+        older = perf_session__new(input_old, O_RDONLY, force, false,
+                                  &diff.tool);
+        newer = perf_session__new(input_new, O_RDONLY, force, false,
+                                  &diff.tool);
         if (session[0] == NULL || session[1] == NULL)
                 return -ENOMEM;
 
         for (i = 0; i < 2; ++i) {
-                ret = perf_session__process_events(session[i], &perf_diff);
+                diff.session = session[i];
+                ret = perf_session__process_events(session[i], &diff.tool);
                 if (ret)
                         goto out_delete;
+                hists__output_resort(&session[i]->hists);
         }
 
-        hists__output_resort(&session[1]->hists);
         if (show_displacement)
-                hists__set_positions(&session[0]->hists);
+                hists__resort_entries(&older->hists);
 
-        hists__match(&session[0]->hists, &session[1]->hists);
-        hists__fprintf(&session[1]->hists, &session[0]->hists,
+        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]);
         return ret;
+#undef older
+#undef newer
 }
 
 static const char * const diff_usage[] = {
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 0221700075c5..d9da62a7234f 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -34,7 +34,7 @@ int __perf_evsel__sample_size(u64 sample_type)
         return size;
 }
 
-static void hists__init(struct hists *hists)
+void hists__init(struct hists *hists)
 {
         memset(hists, 0, sizeof(*hists));
         hists->entries_in_array[0] = hists->entries_in_array[1] = RB_ROOT;
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 3158ca3d69a1..3d6b3e4cb66b 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -170,4 +170,6 @@ static inline int perf_evsel__sample_size(struct perf_evsel *evsel)
         return __perf_evsel__sample_size(evsel->attr.sample_type);
 }
 
+void hists__init(struct hists *hists);
+
 #endif /* __PERF_EVSEL_H */
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 5fb19013ca0c..c61235f81260 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -891,9 +891,9 @@ static int hist_entry__pcnt_snprintf(struct hist_entry *he, char *s,
                 diff = new_percent - old_percent;
 
                 if (fabs(diff) >= 0.01)
-                        ret += scnprintf(bf, sizeof(bf), "%+4.2F%%", diff);
+                        scnprintf(bf, sizeof(bf), "%+4.2F%%", diff);
                 else
-                        ret += scnprintf(bf, sizeof(bf), " ");
+                        scnprintf(bf, sizeof(bf), " ");
 
                 if (sep)
                         ret += scnprintf(s + ret, size - ret, "%c%s", *sep, bf);
@@ -902,9 +902,9 @@ static int hist_entry__pcnt_snprintf(struct hist_entry *he, char *s,
 
                 if (show_displacement) {
                         if (displacement)
-                                ret += scnprintf(bf, sizeof(bf), "%+4ld", displacement);
+                                scnprintf(bf, sizeof(bf), "%+4ld", displacement);
                         else
-                                ret += scnprintf(bf, sizeof(bf), " ");
+                                scnprintf(bf, sizeof(bf), " ");
 
                         if (sep)
                                 ret += scnprintf(s + ret, size - ret, "%c%s", *sep, bf);
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 002ebbf59f48..9412e3b05f68 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -140,6 +140,7 @@ struct perf_session *perf_session__new(const char *filename, int mode,
         INIT_LIST_HEAD(&self->ordered_samples.sample_cache);
         INIT_LIST_HEAD(&self->ordered_samples.to_free);
         machine__init(&self->host_machine, "", HOST_KERNEL_ID);
+        hists__init(&self->hists);
 
         if (mode == O_RDONLY) {
                 if (perf_session__open(self, force) < 0)