3 files changed, 19 insertions, 24 deletions

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 342085a18076..d869029fb75e 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -184,13 +184,9 @@ s64 perf_diff__compute_wdiff(struct hist_entry *he, struct hist_entry *pair)
         return he->diff.wdiff;
 }
 
-static int formula_delta(struct hist_entry *he, char *buf, size_t size)
+static int formula_delta(struct hist_entry *he, struct hist_entry *pair,
+                         char *buf, size_t size)
 {
-        struct hist_entry *pair = hist_entry__next_pair(he);
-
-        if (!pair)
-                return -1;
-
         return scnprintf(buf, size,
                          "(%" PRIu64 " * 100 / %" PRIu64 ") - "
                          "(%" PRIu64 " * 100 / %" PRIu64 ")",
@@ -198,41 +194,36 @@ static int formula_delta(struct hist_entry *he, char *buf, size_t size)
                           pair->stat.period, pair->hists->stats.total_period);
 }
 
-static int formula_ratio(struct hist_entry *he, char *buf, size_t size)
+static int formula_ratio(struct hist_entry *he, struct hist_entry *pair,
+                         char *buf, size_t size)
 {
-        struct hist_entry *pair = hist_entry__next_pair(he);
         double new_period = he->stat.period;
-        double old_period = pair ? pair->stat.period : 0;
-
-        if (!pair)
-                return -1;
+        double old_period = pair->stat.period;
 
         return scnprintf(buf, size, "%.0F / %.0F", new_period, old_period);
 }
 
-static int formula_wdiff(struct hist_entry *he, char *buf, size_t size)
+static int formula_wdiff(struct hist_entry *he, struct hist_entry *pair,
+                         char *buf, size_t size)
 {
-        struct hist_entry *pair = hist_entry__next_pair(he);
         u64 new_period = he->stat.period;
-        u64 old_period = pair ? pair->stat.period : 0;
-
-        if (!pair)
-                return -1;
+        u64 old_period = pair->stat.period;
 
         return scnprintf(buf, size,
                   "(%" PRIu64 " * " "%" PRId64 ") - (%" PRIu64 " * " "%" PRId64 ")",
                   new_period, compute_wdiff_w2, old_period, compute_wdiff_w1);
 }
 
-int perf_diff__formula(char *buf, size_t size, struct hist_entry *he)
+int perf_diff__formula(struct hist_entry *he, struct hist_entry *pair,
+                       char *buf, size_t size)
 {
         switch (compute) {
         case COMPUTE_DELTA:
-                return formula_delta(he, buf, size);
+                return formula_delta(he, pair, buf, size);
         case COMPUTE_RATIO:
-                return formula_ratio(he, buf, size);
+                return formula_ratio(he, pair, buf, size);
         case COMPUTE_WEIGHTED_DIFF:
-                return formula_wdiff(he, buf, size);
+                return formula_wdiff(he, pair, buf, size);
         default:
                 BUG_ON(1);
         }
diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
index 108e5ed67621..1785bab7adfd 100644
--- a/tools/perf/ui/hist.c
+++ b/tools/perf/ui/hist.c
@@ -389,10 +389,13 @@ static int hpp__width_formula(struct perf_hpp *hpp __maybe_unused)
 
 static int hpp__entry_formula(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" : "%-70s";
         char buf[96] = " ";
 
-        perf_diff__formula(buf, sizeof(buf), he);
+        if (pair)
+                perf_diff__formula(he, pair, buf, sizeof(buf));
+
         return scnprintf(hpp->buf, hpp->size, fmt, buf);
 }
 
diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index 235503aac08c..c1b2fade8e70 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -229,6 +229,7 @@ unsigned int hists__sort_list_width(struct hists *self);
 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);
+int perf_diff__formula(struct hist_entry *he, struct hist_entry *pair,
+                       char *buf, size_t size);
 double perf_diff__period_percent(struct hist_entry *he, u64 period);
 #endif  /* __PERF_HIST_H */