3 files changed, 46 insertions, 39 deletions

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 9fbbc01c5ad7..342085a18076 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -146,47 +146,40 @@ static int setup_compute(const struct option *opt, const char *str,
         return -EINVAL;
 }
 
-static double get_period_percent(struct hist_entry *he, u64 period)
+double perf_diff__period_percent(struct hist_entry *he, u64 period)
 {
         u64 total = he->hists->stats.total_period;
         return (period * 100.0) / total;
 }
 
-double perf_diff__compute_delta(struct hist_entry *he)
+double perf_diff__compute_delta(struct hist_entry *he, struct hist_entry *pair)
 {
-        struct hist_entry *pair = hist_entry__next_pair(he);
-        double new_percent = get_period_percent(he, he->stat.period);
-        double old_percent = pair ? get_period_percent(pair, pair->stat.period) : 0.0;
+        double new_percent = perf_diff__period_percent(he, he->stat.period);
+        double old_percent = perf_diff__period_percent(pair, pair->stat.period);
 
         he->diff.period_ratio_delta = new_percent - old_percent;
         he->diff.computed = true;
         return he->diff.period_ratio_delta;
 }
 
-double perf_diff__compute_ratio(struct hist_entry *he)
+double perf_diff__compute_ratio(struct hist_entry *he, struct hist_entry *pair)
 {
-        struct hist_entry *pair = hist_entry__next_pair(he);
         double new_period = he->stat.period;
-        double old_period = pair ? pair->stat.period : 0;
+        double old_period = pair->stat.period;
 
         he->diff.computed = true;
-        he->diff.period_ratio = pair ? (new_period / old_period) : 0;
+        he->diff.period_ratio = new_period / old_period;
         return he->diff.period_ratio;
 }
 
-s64 perf_diff__compute_wdiff(struct hist_entry *he)
+s64 perf_diff__compute_wdiff(struct hist_entry *he, struct hist_entry *pair)
 {
-        struct hist_entry *pair = hist_entry__next_pair(he);
         u64 new_period = he->stat.period;
-        u64 old_period = pair ? pair->stat.period : 0;
+        u64 old_period = pair->stat.period;
 
         he->diff.computed = true;
-
-        if (!pair)
-                he->diff.wdiff = 0;
-        else
-                he->diff.wdiff = new_period * compute_wdiff_w2 -
-                                 old_period * compute_wdiff_w1;
+        he->diff.wdiff = new_period * compute_wdiff_w2 -
+                         old_period * compute_wdiff_w1;
 
         return he->diff.wdiff;
 }
@@ -385,18 +378,21 @@ static void hists__precompute(struct hists *hists)
 
         while (next != NULL) {
                 struct hist_entry *he = rb_entry(next, struct hist_entry, rb_node);
+                struct hist_entry *pair = hist_entry__next_pair(he);
 
                 next = rb_next(&he->rb_node);
+                if (!pair)
+                        continue;
 
                 switch (compute) {
                 case COMPUTE_DELTA:
-                        perf_diff__compute_delta(he);
+                        perf_diff__compute_delta(he, pair);
                         break;
                 case COMPUTE_RATIO:
-                        perf_diff__compute_ratio(he);
+                        perf_diff__compute_ratio(he, pair);
                         break;
                 case COMPUTE_WEIGHTED_DIFF:
-                        perf_diff__compute_wdiff(he);
+                        perf_diff__compute_wdiff(he, pair);
                         break;
                 default:
                         BUG_ON(1);
diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
index 6e639b506829..108e5ed67621 100644
--- a/tools/perf/ui/hist.c
+++ b/tools/perf/ui/hist.c
@@ -268,14 +268,18 @@ static int hpp__width_delta(struct perf_hpp *hpp __maybe_unused)
 
 static int hpp__entry_delta(struct perf_hpp *hpp, struct hist_entry *he)
 {
+        struct hist_entry *pair = hist_entry__next_pair(he);
         const char *fmt = symbol_conf.field_sep ? "%s" : "%7.7s";
         char buf[32] = " ";
-        double diff;
+        double diff = 0.0;
 
-        if (he->diff.computed)
-                diff = he->diff.period_ratio_delta;
-        else
-                diff = perf_diff__compute_delta(he);
+        if (pair) {
+                if (he->diff.computed)
+                        diff = he->diff.period_ratio_delta;
+                else
+                        diff = perf_diff__compute_delta(he, pair);
+        } else
+                diff = perf_diff__period_percent(he, he->stat.period);
 
         if (fabs(diff) >= 0.01)
                 scnprintf(buf, sizeof(buf), "%+4.2F%%", diff);
@@ -297,14 +301,17 @@ static int hpp__width_ratio(struct perf_hpp *hpp __maybe_unused)
 
 static int hpp__entry_ratio(struct perf_hpp *hpp, struct hist_entry *he)
 {
+        struct hist_entry *pair = hist_entry__next_pair(he);
         const char *fmt = symbol_conf.field_sep ? "%s" : "%14s";
         char buf[32] = " ";
-        double ratio;
+        double ratio = 0.0;
 
-        if (he->diff.computed)
-                ratio = he->diff.period_ratio;
-        else
-                ratio = perf_diff__compute_ratio(he);
+        if (pair) {
+                if (he->diff.computed)
+                        ratio = he->diff.period_ratio;
+                else
+                        ratio = perf_diff__compute_ratio(he, pair);
+        }
 
         if (ratio > 0.0)
                 scnprintf(buf, sizeof(buf), "%+14.6F", ratio);
@@ -326,14 +333,17 @@ static int hpp__width_wdiff(struct perf_hpp *hpp __maybe_unused)
 
 static int hpp__entry_wdiff(struct perf_hpp *hpp, struct hist_entry *he)
 {
+        struct hist_entry *pair = hist_entry__next_pair(he);
         const char *fmt = symbol_conf.field_sep ? "%s" : "%14s";
         char buf[32] = " ";
-        s64 wdiff;
+        s64 wdiff = 0;
 
-        if (he->diff.computed)
-                wdiff = he->diff.wdiff;
-        else
-                wdiff = perf_diff__compute_wdiff(he);
+        if (pair) {
+                if (he->diff.computed)
+                        wdiff = he->diff.wdiff;
+                else
+                        wdiff = perf_diff__compute_wdiff(he, pair);
+        }
 
         if (wdiff != 0)
                 scnprintf(buf, sizeof(buf), "%14ld", wdiff);
diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index a935a60d521c..235503aac08c 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -226,8 +226,9 @@ int perf_evlist__gtk_browse_hists(struct perf_evlist *evlist __maybe_unused,
 
 unsigned int hists__sort_list_width(struct hists *self);
 
-double perf_diff__compute_delta(struct hist_entry *he);
-double perf_diff__compute_ratio(struct hist_entry *he);
-s64 perf_diff__compute_wdiff(struct hist_entry *he);
+double perf_diff__compute_delta(struct hist_entry *he, struct hist_entry *pair);
+double perf_diff__compute_ratio(struct hist_entry *he, struct hist_entry *pair);
+s64 perf_diff__compute_wdiff(struct hist_entry *he, struct hist_entry *pair);
 int perf_diff__formula(char *buf, size_t size, struct hist_entry *he);
+double perf_diff__period_percent(struct hist_entry *he, u64 period);
 #endif  /* __PERF_HIST_H */