perf diff: Add -F option to display formula for computation

Adding -F option to display the formula for specified computation.

This is mainly to facilitate debugging, but can be useful anyway.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1349448287-18919-7-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

5 files changed, 96 insertions, 3 deletions

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 21cc2ef7756b..194f37d635df 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -87,6 +87,10 @@ OPTIONS
 --period::
         Show period values for both compared hist entries.
 
+-F::
+--formula::
+        Show formula for given computation.
+
 COMPARISON METHODS
 ------------------
 delta
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 2411dd18c556..dd9c064514f2 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -25,6 +25,7 @@ static char	  diff__default_sort_order[] = "dso,symbol";
 static bool  force;
 static bool show_displacement;
 static bool show_period;
+static bool show_formula;
 static bool show_baseline_only;
 static bool sort_compute;
 
@@ -190,6 +191,62 @@ s64 perf_diff__compute_wdiff(struct hist_entry *he)
         return he->diff.wdiff;
 }
 
+static int formula_delta(struct hist_entry *he, char *buf, size_t size)
+{
+        struct hist_entry *pair = he->pair;
+
+        if (!pair)
+                return -1;
+
+        return scnprintf(buf, size,
+                         "(%" PRIu64 " * 100 / %" PRIu64 ") - "
+                         "(%" PRIu64 " * 100 / %" PRIu64 ")",
+                          he->stat.period, he->hists->stats.total_period,
+                          pair->stat.period, pair->hists->stats.total_period);
+}
+
+static int formula_ratio(struct hist_entry *he, char *buf, size_t size)
+{
+        struct hist_entry *pair = he->pair;
+        double new_period = he->stat.period;
+        double old_period = pair ? pair->stat.period : 0;
+
+        if (!pair)
+                return -1;
+
+        return scnprintf(buf, size, "%.0F / %.0F", new_period, old_period);
+}
+
+static int formula_wdiff(struct hist_entry *he, char *buf, size_t size)
+{
+        struct hist_entry *pair = he->pair;
+        u64 new_period = he->stat.period;
+        u64 old_period = pair ? pair->stat.period : 0;
+
+        if (!pair)
+                return -1;
+
+        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)
+{
+        switch (compute) {
+        case COMPUTE_DELTA:
+                return formula_delta(he, buf, size);
+        case COMPUTE_RATIO:
+                return formula_ratio(he, buf, size);
+        case COMPUTE_WEIGHTED_DIFF:
+                return formula_wdiff(he, buf, size);
+        default:
+                BUG_ON(1);
+        }
+
+        return -1;
+}
+
 static int hists__add_entry(struct hists *self,
                             struct addr_location *al, u64 period)
 {
@@ -543,6 +600,8 @@ static const struct option options[] = {
                      setup_compute),
         OPT_BOOLEAN('p', "period", &show_period,
                     "Show period values."),
+        OPT_BOOLEAN('F', "formula", &show_formula,
+                    "Show formula."),
         OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
                     "dump raw trace in ASCII"),
         OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
@@ -571,7 +630,10 @@ static void ui_init(void)
         /* No overhead column. */
         perf_hpp__column_enable(PERF_HPP__OVERHEAD, false);
 
-        /* Display baseline/delta/ratio/displacement/periods columns. */
+        /*
+         * Display baseline/delta/ratio/displacement/
+         * formula/periods columns.
+         */
         perf_hpp__column_enable(PERF_HPP__BASELINE, true);
 
         switch (compute) {
@@ -591,6 +653,9 @@ static void ui_init(void)
         if (show_displacement)
                 perf_hpp__column_enable(PERF_HPP__DISPL, true);
 
+        if (show_formula)
+                perf_hpp__column_enable(PERF_HPP__FORMULA, true);
+
         if (show_period) {
                 perf_hpp__column_enable(PERF_HPP__PERIOD, true);
                 perf_hpp__column_enable(PERF_HPP__PERIOD_BASELINE, true);
diff --git a/tools/perf/ui/hist.c b/tools/perf/ui/hist.c
index 2fadaff6312f..305eb79f4af4 100644
--- a/tools/perf/ui/hist.c
+++ b/tools/perf/ui/hist.c
@@ -359,6 +359,27 @@ static int hpp__entry_displ(struct perf_hpp *hpp,
         return scnprintf(hpp->buf, hpp->size, fmt, buf);
 }
 
+static int hpp__header_formula(struct perf_hpp *hpp)
+{
+        const char *fmt = symbol_conf.field_sep ? "%s" : "%70s";
+
+        return scnprintf(hpp->buf, hpp->size, fmt, "Formula");
+}
+
+static int hpp__width_formula(struct perf_hpp *hpp __maybe_unused)
+{
+        return 70;
+}
+
+static int hpp__entry_formula(struct perf_hpp *hpp, struct hist_entry *he)
+{
+        const char *fmt = symbol_conf.field_sep ? "%s" : "%-70s";
+        char buf[96] = " ";
+
+        perf_diff__formula(buf, sizeof(buf), he);
+        return scnprintf(hpp->buf, hpp->size, fmt, buf);
+}
+
 #define HPP__COLOR_PRINT_FNS(_name)             \
         .header = hpp__header_ ## _name,                \
         .width  = hpp__width_ ## _name,         \
@@ -383,7 +404,8 @@ struct perf_hpp_fmt perf_hpp__format[] = {
         { .cond = false, HPP__PRINT_FNS(delta) },
         { .cond = false, HPP__PRINT_FNS(ratio) },
         { .cond = false, HPP__PRINT_FNS(wdiff) },
-        { .cond = false, HPP__PRINT_FNS(displ) }
+        { .cond = false, HPP__PRINT_FNS(displ) },
+        { .cond = false, HPP__PRINT_FNS(formula) }
 };
 
 #undef HPP__COLOR_PRINT_FNS
diff --git a/tools/perf/ui/stdio/hist.c b/tools/perf/ui/stdio/hist.c
index fbd4e32d0743..f0ee204f99bb 100644
--- a/tools/perf/ui/stdio/hist.c
+++ b/tools/perf/ui/stdio/hist.c
@@ -342,7 +342,7 @@ size_t hists__fprintf(struct hists *hists, bool show_header, int max_rows,
         const char *sep = symbol_conf.field_sep;
         const char *col_width = symbol_conf.col_width_list_str;
         int idx, nr_rows = 0;
-        char bf[64];
+        char bf[96];
         struct perf_hpp dummy_hpp = {
                 .buf    = bf,
                 .size   = sizeof(bf),
diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index 5604791e5ede..c751624d4153 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -145,6 +145,7 @@ enum {
         PERF_HPP__RATIO,
         PERF_HPP__WEIGHTED_DIFF,
         PERF_HPP__DISPL,
+        PERF_HPP__FORMULA,
 
         PERF_HPP__MAX_INDEX
 };
@@ -210,4 +211,5 @@ 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);
+int perf_diff__formula(char *buf, size_t size, struct hist_entry *he);
 #endif  /* __PERF_HIST_H */