perf diff: Change diff command to work over multiple data files

Adding diff command the flexibility to specify multiple data files on
input. If not input file is given the standard behaviour stands and diff
inspects 'perf.data' and 'perf.data.old' files.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
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/n/tip-8j3xer54ltvs76t0fh01gcvu@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-diff.c

@@ -44,6 +44,7 @@ struct data__file {
 	struct perf_session	*session;
 	const char		*file;
 	int			 idx;
+	struct hists		*hists;
 	struct diff_hpp_fmt	 fmt[PERF_HPP_DIFF__MAX_INDEX];
 };
 
@@ -56,6 +57,7 @@ static int data__files_cnt;
 	     i++, d = &data__files[i])
 
 #define data__for_each_file(i, d) data__for_each_file_start(i, d, 0)
+#define data__for_each_file_new(i, d) data__for_each_file_start(i, d, 1)
 
 static char diff__default_sort_order[] = "dso,symbol";
 static bool force;
@@ -525,23 +527,19 @@ static void hists__compute_resort(struct hists *hists)
 	}
 }
 
-static void hists__process(struct hists *base, struct hists *new)
+static void hists__process(struct hists *hists)
 {
-	hists__match(base, new);
-
 	if (show_baseline_only)
-		hists__baseline_only(base);
-	else
-		hists__link(base, new);
+		hists__baseline_only(hists);
 
 	if (sort_compute) {
-		hists__precompute(base);
-		hists__compute_resort(base);
+		hists__precompute(hists);
+		hists__compute_resort(hists);
 	} else {
-		hists__output_resort(base);
+		hists__output_resort(hists);
 	}
 
-	hists__fprintf(base, true, 0, 0, 0, stdout);
+	hists__fprintf(hists, true, 0, 0, 0, stdout);
 }
 
 static void data__fprintf(void)
@@ -561,27 +559,40 @@ static void data__fprintf(void)
 
 static void data_process(void)
 {
-	struct perf_evlist *evlist_old = data__files[0].session->evlist;
-	struct perf_evlist *evlist_new = data__files[1].session->evlist;
-	struct perf_evsel *evsel_old;
+	struct perf_evlist *evlist_base = data__files[0].session->evlist;
+	struct perf_evsel *evsel_base;
 	bool first = true;
 
-	list_for_each_entry(evsel_old, &evlist_old->entries, node) {
-		struct perf_evsel *evsel_new;
+	list_for_each_entry(evsel_base, &evlist_base->entries, node) {
+		struct data__file *d;
+		int i;
 
-		evsel_new = evsel_match(evsel_old, evlist_new);
-		if (!evsel_new)
-			continue;
+		data__for_each_file_new(i, d) {
+			struct perf_evlist *evlist = d->session->evlist;
+			struct perf_evsel *evsel;
+
+			evsel = evsel_match(evsel_base, evlist);
+			if (!evsel)
+				continue;
+
+			d->hists = &evsel->hists;
+
+			hists__match(&evsel_base->hists, &evsel->hists);
+
+			if (!show_baseline_only)
+				hists__link(&evsel_base->hists,
+					    &evsel->hists);
+		}
 
 		fprintf(stdout, "%s# Event '%s'\n#\n", first ? "" : "\n",
-			perf_evsel__name(evsel_old));
+			perf_evsel__name(evsel_base));
 
 		first = false;
 
-		if (verbose)
+		if (verbose || data__files_cnt > 2)
 			data__fprintf();
 
-		hists__process(&evsel_old->hists, &evsel_new->hists);
+		hists__process(&evsel_base->hists);
 	}
 }
 
@@ -780,10 +791,29 @@ hpp__entry_pair(struct hist_entry *he, struct hist_entry *pair,
 	};
 }
 
+static struct hist_entry *get_pair(struct hist_entry *he,
+				   struct diff_hpp_fmt *dfmt)
+{
+	void *ptr = dfmt - dfmt->idx;
+	struct data__file *d = container_of(ptr, struct data__file, fmt);
+
+	if (hist_entry__has_pairs(he)) {
+		struct hist_entry *pair;
+
+		list_for_each_entry(pair, &he->pairs.head, pairs.node)
+			if (pair->hists == d->hists)
+				return pair;
+	}
+
+	return NULL;
+}
+
 static void
-__hpp__entry_global(struct hist_entry *he, int idx, char *buf, size_t size)
+__hpp__entry_global(struct hist_entry *he, struct diff_hpp_fmt *dfmt,
+		    char *buf, size_t size)
 {
-	struct hist_entry *pair = hist_entry__next_pair(he);
+	struct hist_entry *pair = get_pair(he, dfmt);
+	int idx = dfmt->idx;
 
 	/* baseline is special */
 	if (idx == PERF_HPP_DIFF__BASELINE)
@@ -803,7 +833,7 @@ static int hpp__entry_global(struct perf_hpp_fmt *_fmt, struct perf_hpp *hpp,
 		container_of(_fmt, struct diff_hpp_fmt, fmt);
 	char buf[MAX_COL_WIDTH] = " ";
 
-	__hpp__entry_global(he, dfmt->idx, buf, MAX_COL_WIDTH);
+	__hpp__entry_global(he, dfmt, buf, MAX_COL_WIDTH);
 
 	if (symbol_conf.field_sep)
 		return scnprintf(hpp->buf, hpp->size, "%s", buf);
@@ -832,7 +862,7 @@ static int hpp__width(struct perf_hpp_fmt *fmt,
 	return dfmt->header_width;
 }
 
-static void init_header(struct diff_hpp_fmt *dfmt)
+static void init_header(struct data__file *d, struct diff_hpp_fmt *dfmt)
 {
 #define MAX_HEADER_NAME 100
 	char buf_indent[MAX_HEADER_NAME];
@@ -847,6 +877,9 @@ static void init_header(struct diff_hpp_fmt *dfmt)
 	/* Only our defined HPP fmts should appear here. */
 	BUG_ON(!header);
 
+	if (data__files_cnt > 2)
+		scnprintf(buf, MAX_HEADER_NAME, "%s/%d", header, d->idx);
+
 #define NAME (data__files_cnt > 2 ? buf : header)
 	dfmt->header_width = width;
 	width = (int) strlen(NAME);
@@ -876,7 +909,7 @@ static void data__hpp_register(struct data__file *d, int idx)
 	if (idx == PERF_HPP_DIFF__BASELINE)
 		fmt->color = hpp__color_baseline;
 
-	init_header(dfmt);
+	init_header(d, dfmt);
 	perf_hpp__column_register(fmt);
 }
 
@@ -921,18 +954,18 @@ static int data_init(int argc, const char **argv)
 		"perf.data.old",
 		"perf.data",
 	};
+	bool use_default = true;
 	int i;
 
 	data__files_cnt = 2;
 
 	if (argc) {
-		if (argc > 2)
-			usage_with_options(diff_usage, options);
-		if (argc == 2) {
-			defaults[0] = argv[0];
-			defaults[1] = argv[1];
-		} else
+		if (argc == 1)
 			defaults[1] = argv[0];
+		else {
+			data__files_cnt = argc;
+			use_default = false;
+		}
 	} else if (symbol_conf.default_guest_vmlinux_name ||
 		   symbol_conf.default_guest_kallsyms) {
 		defaults[0] = "perf.data.host";
@@ -944,7 +977,7 @@ static int data_init(int argc, const char **argv)
 		return -ENOMEM;
 
 	data__for_each_file(i, d) {
-		d->file = defaults[i];
+		d->file = use_default ? defaults[i] : argv[i];
 		d->idx  = i;
 	}