[PATCH 09/12] perf diff: Add weighted diff computation way to compare hist entries

[Jiri Olsa <jolsa@redhat.com>]

Adding 'wdiff' as new computation way to compare hist entries.

If specified the 'Weighted diff' column is displayed with value 'd'
computed as:

   d = B->period * WEIGHT-A - A->period * WEIGHT-B

  - A/B being matching hist entry from first/second file specified
    (or perf.data/perf.data.old) respectively.

  - period being the hist entry period value

  - WEIGHT-A/WEIGHT-B being user suplied weights in the the '-c' option
    behind ':' separator like '-c wdiff:1,2'.

Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
---
 tools/perf/Documentation/perf-diff.txt | 15 +++++-
 tools/perf/builtin-diff.c              | 95 +++++++++++++++++++++++++++++++++-
 tools/perf/ui/stdio/hist.c             | 15 ++++++
 tools/perf/ui/stdio/hist.h             |  1 +
 tools/perf/util/hist.h                 |  1 +
 tools/perf/util/sort.h                 |  3 ++
 6 files changed, 127 insertions(+), 3 deletions(-)

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index cff3d9b..fa413ac 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -78,7 +78,7 @@ OPTIONS
 
 -c::
 --compute::
-        Differential computation selection - delta,ratio (default is delta).
+        Differential computation selection - delta,ratio,wdiff (default is delta).
         If '+' is specified as a first character, the output is sorted based
         on the computation results.
         See COMPARISON METHODS section for more info.
@@ -110,6 +110,19 @@ with:
 
   - period being the hist entry period value
 
+wdiff
+~~~~~
+If specified the 'Weighted diff' column is displayed with value 'd' computed as:
+
+   d = B->period * WEIGHT-A - A->period * WEIGHT-B
+
+  - A/B being matching hist entry from first/second file specified
+    (or perf.data/perf.data.old) respectively.
+
+  - period being the hist entry period value
+
+  - WEIGHT-A/WEIGHT-B being user suplied weights in the the '-c' option
+    behind ':' separator like '-c wdiff:1,2'.
 
 SEE ALSO
 --------
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index f72a2e4..6d8aba8 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -28,23 +28,79 @@ static bool show_displacement;
 static bool show_baseline_only;
 static bool sort_compute;
 
+static s64 compute_wdiff_w1;
+static s64 compute_wdiff_w2;
+
 enum {
 	COMPUTE_DELTA,
 	COMPUTE_RATIO,
+	COMPUTE_WEIGHTED_DIFF,
 	COMPUTE_MAX,
 };
 
 const char *compute_names[COMPUTE_MAX] = {
 	[COMPUTE_DELTA] = "delta",
 	[COMPUTE_RATIO] = "ratio",
+	[COMPUTE_WEIGHTED_DIFF] = "wdiff",
 };
 
 static const char *compute_str;
 static int compute;
 
+static int setup_compute_opt_wdiff(char *opt)
+{
+	char *w1_str = opt;
+	char *w2_str;
+
+	int ret = -EINVAL;
+
+	do {
+		if (!opt)
+			break;
+
+		w2_str = strchr(opt, ',');
+		if (!w2_str)
+			break;
+
+		*w2_str++ = 0x0;
+		if (!*w2_str)
+			break;
+
+		compute_wdiff_w1 = strtol(w1_str, NULL, 10);
+		compute_wdiff_w2 = strtol(w2_str, NULL, 10);
+
+		if (!compute_wdiff_w1 || !compute_wdiff_w2)
+			break;
+
+		pr_debug("compute wdiff w1(%" PRId64 ") w2(%" PRId64 ")\n",
+			  compute_wdiff_w1, compute_wdiff_w2);
+		ret = 0;
+
+	} while (0);
+
+	if (ret)
+		pr_err("Weight parsing failed.");
+
+	return ret;
+}
+
+static int setup_compute_opt(char *opt)
+{
+	if (compute == COMPUTE_WEIGHTED_DIFF)
+		return setup_compute_opt_wdiff(opt);
+
+	if (opt) {
+		pr_err("Extra option specified.");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int setup_compute(void)
 {
 	unsigned i;
+	char *opt;
 
 	if (!compute_str) {
 		compute = COMPUTE_DELTA;
@@ -58,10 +114,14 @@ static int setup_compute(void)
 			return 0;
 	}
 
+	opt = strchr(compute_str, ':');
+	if (opt)
+		*opt++ = 0x0;
+
 	for (i = 0; i < COMPUTE_MAX; i++)
 		if (!strcmp(compute_str, compute_names[i])) {
 			compute = i;
-			return 0;
+			return setup_compute_opt(opt);
 		}
 
 	pr_err("Failed to find valid compute string\n");
@@ -96,6 +156,23 @@ double perf_diff__compute_ratio(struct hist_entry *he)
 	return he->diff.period_ratio;
 }
 
+double perf_diff__compute_wdiff(struct hist_entry *he)
+{
+	struct hist_entry *pair = he->pair;
+	u64 new_period = he->period;
+	u64 old_period = pair ? pair->period : 0;
+
+	he->diff.computed = true;
+
+	if (!pair)
+		he->diff.wdiff = 0;
+	else
+		he->diff.wdiff = new_period * compute_wdiff_w2 -
+				 old_period * compute_wdiff_w1;
+
+	return he->diff.wdiff;
+}
+
 static int hists__add_entry(struct hists *self,
 			    struct addr_location *al, u64 period)
 {
@@ -277,6 +354,9 @@ static void hists__precompute(struct hists *hists)
 		case COMPUTE_RATIO:
 			perf_diff__compute_ratio(he);
 			break;
+		case COMPUTE_WEIGHTED_DIFF:
+			perf_diff__compute_wdiff(he);
+			break;
 		default:
 			BUG_ON(1);
 		}
@@ -312,6 +392,13 @@ hist_entry__cmp_compute(struct hist_entry *left, struct hist_entry *right,
 
 		return cmp_doubles(l, r);
 	}
+	case COMPUTE_WEIGHTED_DIFF:
+	{
+		s64 l = left->diff.wdiff;
+		s64 r = right->diff.wdiff;
+
+		return r - l;
+	}
 	default:
 		BUG_ON(1);
 	}
@@ -436,7 +523,8 @@ static const struct option options[] = {
 		    "Show position displacement relative to baseline"),
 	OPT_BOOLEAN('b', "baseline-only", &show_baseline_only,
 		    "Show only items with match in baseline"),
-	OPT_STRING('c', "compute", &compute_str, "delta,ratio (default delta)",
+	OPT_STRING('c', "compute", &compute_str,
+		   "delta,ratio,wdiff:w1,w2 (default delta)",
 		   "Entries differential computation selection"),
 	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,
 		    "dump raw trace in ASCII"),
@@ -471,6 +559,9 @@ static void setup_ui_stdio(void)
 	case COMPUTE_RATIO:
 		hists_stdio_column__register_idx(HISTC_RATIO);
 		break;
+	case COMPUTE_WEIGHTED_DIFF:
+		hists_stdio_column__register_idx(HISTC_WEIGHTED_DIFF);
+		break;
 	default:
 		BUG_ON(1);
 	};
diff --git a/tools/perf/ui/stdio/hist.c b/tools/perf/ui/stdio/hist.c
index 8c717ab..f580085 100644
--- a/tools/perf/ui/stdio/hist.c
+++ b/tools/perf/ui/stdio/hist.c
@@ -47,6 +47,20 @@ hists_stdio_column__ratio_snprintf(struct hist_entry *he, char *bf,
 }
 
 static int
+hists_stdio_column__wdiff_snprintf(struct hist_entry *he, char *bf,
+				   size_t size, unsigned int width __used)
+{
+	u64 wdiff;
+
+	if (he->diff.computed)
+		wdiff = he->diff.wdiff;
+	else
+		wdiff = perf_diff__compute_wdiff(he);
+
+	return scnprintf(bf, size , "%+13ld", wdiff);
+}
+
+static int
 hists_stdio_column__baseline_snprintf(struct hist_entry *he, char *bf,
 				      size_t size, unsigned int width __used)
 {
@@ -141,6 +155,7 @@ DEF_COLUMN(nr_samples, HISTC_NR_SAMPLES, 12, "Samples")
 DEF_COLUMN(total_period, HISTC_TOTAL_PERIOD, 12, "Period")
 DEF_COLUMN(delta, HISTC_DELTA, 8, "Delta")
 DEF_COLUMN(ratio, HISTC_RATIO, 14, "Ratio")
+DEF_COLUMN(wdiff, HISTC_WEIGHTED_DIFF, 13, "Weighted diff")
 DEF_COLUMN(displacement, HISTC_DISPLACEMENT, 5, "Displ")
 };
 
diff --git a/tools/perf/ui/stdio/hist.h b/tools/perf/ui/stdio/hist.h
index c8ac633..f725189 100644
--- a/tools/perf/ui/stdio/hist.h
+++ b/tools/perf/ui/stdio/hist.h
@@ -19,5 +19,6 @@ void hists_stdio_column__set_width(struct hists *hists);
 
 double perf_diff__compute_delta(struct hist_entry *he);
 double perf_diff__compute_ratio(struct hist_entry *he);
+double perf_diff__compute_wdiff(struct hist_entry *he);
 
 #endif /* __PERF_UI_STDIO_HIST_H */
diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index b24341d..745e0cc 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -47,6 +47,7 @@ enum hist_column {
 	HISTC_TOTAL_PERIOD,
 	HISTC_DELTA,
 	HISTC_RATIO,
+	HISTC_WEIGHTED_DIFF,
 	HISTC_DISPLACEMENT,
 
 	/* sorted (hist_entry__sort_list) */
diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
index 9f707b7..73f1ffe 100644
--- a/tools/perf/util/sort.h
+++ b/tools/perf/util/sort.h
@@ -53,6 +53,9 @@ struct hist_entry_diff {
 
 	/* HISTC_RATIO */
 	double	period_ratio;
+
+	/* HISTC_WEIGHTED_DIFF */
+	s64	wdiff;
 };
 
 /**
-- 
1.7.11.4