diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
new file mode 100644
index 0000000..39db2ee
--- /dev/null
+++ b/tools/perf/builtin-diff.c
@@ -0,0 +1,1363 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * builtin-diff.c
+ *
+ * Builtin diff command: Analyze two perf.data input files, look up and read
+ * DSOs and symbol information, sort them and produce a diff.
+ */
+#include "builtin.h"
+
+#include "util/debug.h"
+#include "util/event.h"
+#include "util/hist.h"
+#include "util/evsel.h"
+#include "util/evlist.h"
+#include "util/session.h"
+#include "util/tool.h"
+#include "util/sort.h"
+#include "util/symbol.h"
+#include "util/util.h"
+#include "util/data.h"
+#include "util/config.h"
+
+#include <errno.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <math.h>
+
+/* Diff command specific HPP columns. */
+enum {
+	PERF_HPP_DIFF__BASELINE,
+	PERF_HPP_DIFF__PERIOD,
+	PERF_HPP_DIFF__PERIOD_BASELINE,
+	PERF_HPP_DIFF__DELTA,
+	PERF_HPP_DIFF__RATIO,
+	PERF_HPP_DIFF__WEIGHTED_DIFF,
+	PERF_HPP_DIFF__FORMULA,
+	PERF_HPP_DIFF__DELTA_ABS,
+
+	PERF_HPP_DIFF__MAX_INDEX
+};
+
+struct diff_hpp_fmt {
+	struct perf_hpp_fmt	 fmt;
+	int			 idx;
+	char			*header;
+	int			 header_width;
+};
+
+struct data__file {
+	struct perf_session	*session;
+	struct perf_data	 data;
+	int			 idx;
+	struct hists		*hists;
+	struct diff_hpp_fmt	 fmt[PERF_HPP_DIFF__MAX_INDEX];
+};
+
+static struct data__file *data__files;
+static int data__files_cnt;
+
+#define data__for_each_file_start(i, d, s)	\
+	for (i = s, d = &data__files[s];	\
+	     i < 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 bool force;
+static bool show_period;
+static bool show_formula;
+static bool show_baseline_only;
+static unsigned int sort_compute = 1;
+
+static s64 compute_wdiff_w1;
+static s64 compute_wdiff_w2;
+
+enum {
+	COMPUTE_DELTA,
+	COMPUTE_RATIO,
+	COMPUTE_WEIGHTED_DIFF,
+	COMPUTE_DELTA_ABS,
+	COMPUTE_MAX,
+};
+
+const char *compute_names[COMPUTE_MAX] = {
+	[COMPUTE_DELTA] = "delta",
+	[COMPUTE_DELTA_ABS] = "delta-abs",
+	[COMPUTE_RATIO] = "ratio",
+	[COMPUTE_WEIGHTED_DIFF] = "wdiff",
+};
+
+static int compute = COMPUTE_DELTA_ABS;
+
+static int compute_2_hpp[COMPUTE_MAX] = {
+	[COMPUTE_DELTA]		= PERF_HPP_DIFF__DELTA,
+	[COMPUTE_DELTA_ABS]	= PERF_HPP_DIFF__DELTA_ABS,
+	[COMPUTE_RATIO]		= PERF_HPP_DIFF__RATIO,
+	[COMPUTE_WEIGHTED_DIFF]	= PERF_HPP_DIFF__WEIGHTED_DIFF,
+};
+
+#define MAX_COL_WIDTH 70
+
+static struct header_column {
+	const char *name;
+	int width;
+} columns[PERF_HPP_DIFF__MAX_INDEX] = {
+	[PERF_HPP_DIFF__BASELINE] = {
+		.name  = "Baseline",
+	},
+	[PERF_HPP_DIFF__PERIOD] = {
+		.name  = "Period",
+		.width = 14,
+	},
+	[PERF_HPP_DIFF__PERIOD_BASELINE] = {
+		.name  = "Base period",
+		.width = 14,
+	},
+	[PERF_HPP_DIFF__DELTA] = {
+		.name  = "Delta",
+		.width = 7,
+	},
+	[PERF_HPP_DIFF__DELTA_ABS] = {
+		.name  = "Delta Abs",
+		.width = 7,
+	},
+	[PERF_HPP_DIFF__RATIO] = {
+		.name  = "Ratio",
+		.width = 14,
+	},
+	[PERF_HPP_DIFF__WEIGHTED_DIFF] = {
+		.name  = "Weighted diff",
+		.width = 14,
+	},
+	[PERF_HPP_DIFF__FORMULA] = {
+		.name  = "Formula",
+		.width = MAX_COL_WIDTH,
+	}
+};
+
+static int setup_compute_opt_wdiff(char *opt)
+{
+	char *w1_str = opt;
+	char *w2_str;
+
+	int ret = -EINVAL;
+
+	if (!opt)
+		goto out;
+
+	w2_str = strchr(opt, ',');
+	if (!w2_str)
+		goto out;
+
+	*w2_str++ = 0x0;
+	if (!*w2_str)
+		goto out;
+
+	compute_wdiff_w1 = strtol(w1_str, NULL, 10);
+	compute_wdiff_w2 = strtol(w2_str, NULL, 10);
+
+	if (!compute_wdiff_w1 || !compute_wdiff_w2)
+		goto out;
+
+	pr_debug("compute wdiff w1(%" PRId64 ") w2(%" PRId64 ")\n",
+		  compute_wdiff_w1, compute_wdiff_w2);
+
+	ret = 0;
+
+ out:
+	if (ret)
+		pr_err("Failed: wrong weight data, use 'wdiff:w1,w2'\n");
+
+	return ret;
+}
+
+static int setup_compute_opt(char *opt)
+{
+	if (compute == COMPUTE_WEIGHTED_DIFF)
+		return setup_compute_opt_wdiff(opt);
+
+	if (opt) {
+		pr_err("Failed: extra option specified '%s'", opt);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int setup_compute(const struct option *opt, const char *str,
+			 int unset __maybe_unused)
+{
+	int *cp = (int *) opt->value;
+	char *cstr = (char *) str;
+	char buf[50];
+	unsigned i;
+	char *option;
+
+	if (!str) {
+		*cp = COMPUTE_DELTA;
+		return 0;
+	}
+
+	option = strchr(str, ':');
+	if (option) {
+		unsigned len = option++ - str;
+
+		/*
+		 * The str data are not writeable, so we need
+		 * to use another buffer.
+		 */
+
+		/* No option value is longer. */
+		if (len >= sizeof(buf))
+			return -EINVAL;
+
+		strncpy(buf, str, len);
+		buf[len] = 0x0;
+		cstr = buf;
+	}
+
+	for (i = 0; i < COMPUTE_MAX; i++)
+		if (!strcmp(cstr, compute_names[i])) {
+			*cp = i;
+			return setup_compute_opt(option);
+		}
+
+	pr_err("Failed: '%s' is not computation method "
+	       "(use 'delta','ratio' or 'wdiff')\n", str);
+	return -EINVAL;
+}
+
+static double period_percent(struct hist_entry *he, u64 period)
+{
+	u64 total = hists__total_period(he->hists);
+
+	return (period * 100.0) / total;
+}
+
+static double compute_delta(struct hist_entry *he, struct hist_entry *pair)
+{
+	double old_percent = period_percent(he, he->stat.period);
+	double new_percent = period_percent(pair, pair->stat.period);
+
+	pair->diff.period_ratio_delta = new_percent - old_percent;
+	pair->diff.computed = true;
+	return pair->diff.period_ratio_delta;
+}
+
+static double compute_ratio(struct hist_entry *he, struct hist_entry *pair)
+{
+	double old_period = he->stat.period ?: 1;
+	double new_period = pair->stat.period;
+
+	pair->diff.computed = true;
+	pair->diff.period_ratio = new_period / old_period;
+	return pair->diff.period_ratio;
+}
+
+static s64 compute_wdiff(struct hist_entry *he, struct hist_entry *pair)
+{
+	u64 old_period = he->stat.period;
+	u64 new_period = pair->stat.period;
+
+	pair->diff.computed = true;
+	pair->diff.wdiff = new_period * compute_wdiff_w2 -
+			   old_period * compute_wdiff_w1;
+
+	return pair->diff.wdiff;
+}
+
+static int formula_delta(struct hist_entry *he, struct hist_entry *pair,
+			 char *buf, size_t size)
+{
+	u64 he_total = he->hists->stats.total_period;
+	u64 pair_total = pair->hists->stats.total_period;
+
+	if (symbol_conf.filter_relative) {
+		he_total = he->hists->stats.total_non_filtered_period;
+		pair_total = pair->hists->stats.total_non_filtered_period;
+	}
+	return scnprintf(buf, size,
+			 "(%" PRIu64 " * 100 / %" PRIu64 ") - "
+			 "(%" PRIu64 " * 100 / %" PRIu64 ")",
+			 pair->stat.period, pair_total,
+			 he->stat.period, he_total);
+}
+
+static int formula_ratio(struct hist_entry *he, struct hist_entry *pair,
+			 char *buf, size_t size)
+{
+	double old_period = he->stat.period;
+	double new_period = pair->stat.period;
+
+	return scnprintf(buf, size, "%.0F / %.0F", new_period, old_period);
+}
+
+static int formula_wdiff(struct hist_entry *he, struct hist_entry *pair,
+			 char *buf, size_t size)
+{
+	u64 old_period = he->stat.period;
+	u64 new_period = pair->stat.period;
+
+	return scnprintf(buf, size,
+		  "(%" PRIu64 " * " "%" PRId64 ") - (%" PRIu64 " * " "%" PRId64 ")",
+		  new_period, compute_wdiff_w2, old_period, compute_wdiff_w1);
+}
+
+static int formula_fprintf(struct hist_entry *he, struct hist_entry *pair,
+			   char *buf, size_t size)
+{
+	switch (compute) {
+	case COMPUTE_DELTA:
+	case COMPUTE_DELTA_ABS:
+		return formula_delta(he, pair, buf, size);
+	case COMPUTE_RATIO:
+		return formula_ratio(he, pair, buf, size);
+	case COMPUTE_WEIGHTED_DIFF:
+		return formula_wdiff(he, pair, buf, size);
+	default:
+		BUG_ON(1);
+	}
+
+	return -1;
+}
+
+static int diff__process_sample_event(struct perf_tool *tool __maybe_unused,
+				      union perf_event *event,
+				      struct perf_sample *sample,
+				      struct perf_evsel *evsel,
+				      struct machine *machine)
+{
+	struct addr_location al;
+	struct hists *hists = evsel__hists(evsel);
+	int ret = -1;
+
+	if (machine__resolve(machine, &al, sample) < 0) {
+		pr_warning("problem processing %d event, skipping it.\n",
+			   event->header.type);
+		return -1;
+	}
+
+	if (!hists__add_entry(hists, &al, NULL, NULL, NULL, sample, true)) {
+		pr_warning("problem incrementing symbol period, skipping event\n");
+		goto out_put;
+	}
+
+	/*
+	 * The total_period is updated here before going to the output
+	 * tree since normally only the baseline hists will call
+	 * hists__output_resort() and precompute needs the total
+	 * period in order to sort entries by percentage delta.
+	 */
+	hists->stats.total_period += sample->period;
+	if (!al.filtered)
+		hists->stats.total_non_filtered_period += sample->period;
+	ret = 0;
+out_put:
+	addr_location__put(&al);
+	return ret;
+}
+
+static struct perf_tool tool = {
+	.sample	= diff__process_sample_event,
+	.mmap	= perf_event__process_mmap,
+	.mmap2	= perf_event__process_mmap2,
+	.comm	= perf_event__process_comm,
+	.exit	= perf_event__process_exit,
+	.fork	= perf_event__process_fork,
+	.lost	= perf_event__process_lost,
+	.namespaces = perf_event__process_namespaces,
+	.ordered_events = true,
+	.ordering_requires_timestamps = true,
+};
+
+static struct perf_evsel *evsel_match(struct perf_evsel *evsel,
+				      struct perf_evlist *evlist)
+{
+	struct perf_evsel *e;
+
+	evlist__for_each_entry(evlist, e) {
+		if (perf_evsel__match2(evsel, e))
+			return e;
+	}
+
+	return NULL;
+}
+
+static void perf_evlist__collapse_resort(struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+
+	evlist__for_each_entry(evlist, evsel) {
+		struct hists *hists = evsel__hists(evsel);
+
+		hists__collapse_resort(hists, NULL);
+	}
+}
+
+static struct data__file *fmt_to_data_file(struct perf_hpp_fmt *fmt)
+{
+	struct diff_hpp_fmt *dfmt = container_of(fmt, struct diff_hpp_fmt, fmt);
+	void *ptr = dfmt - dfmt->idx;
+	struct data__file *d = container_of(ptr, struct data__file, fmt);
+
+	return d;
+}
+
+static struct hist_entry*
+get_pair_data(struct hist_entry *he, struct data__file *d)
+{
+	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 struct hist_entry*
+get_pair_fmt(struct hist_entry *he, struct diff_hpp_fmt *dfmt)
+{
+	struct data__file *d = fmt_to_data_file(&dfmt->fmt);
+
+	return get_pair_data(he, d);
+}
+
+static void hists__baseline_only(struct hists *hists)
+{
+	struct rb_root *root;
+	struct rb_node *next;
+
+	if (hists__has(hists, need_collapse))
+		root = &hists->entries_collapsed;
+	else
+		root = hists->entries_in;
+
+	next = rb_first(root);
+	while (next != NULL) {
+		struct hist_entry *he = rb_entry(next, struct hist_entry, rb_node_in);
+
+		next = rb_next(&he->rb_node_in);
+		if (!hist_entry__next_pair(he)) {
+			rb_erase(&he->rb_node_in, root);
+			hist_entry__delete(he);
+		}
+	}
+}
+
+static void hists__precompute(struct hists *hists)
+{
+	struct rb_root *root;
+	struct rb_node *next;
+
+	if (hists__has(hists, need_collapse))
+		root = &hists->entries_collapsed;
+	else
+		root = hists->entries_in;
+
+	next = rb_first(root);
+	while (next != NULL) {
+		struct hist_entry *he, *pair;
+		struct data__file *d;
+		int i;
+
+		he   = rb_entry(next, struct hist_entry, rb_node_in);
+		next = rb_next(&he->rb_node_in);
+
+		data__for_each_file_new(i, d) {
+			pair = get_pair_data(he, d);
+			if (!pair)
+				continue;
+
+			switch (compute) {
+			case COMPUTE_DELTA:
+			case COMPUTE_DELTA_ABS:
+				compute_delta(he, pair);
+				break;
+			case COMPUTE_RATIO:
+				compute_ratio(he, pair);
+				break;
+			case COMPUTE_WEIGHTED_DIFF:
+				compute_wdiff(he, pair);
+				break;
+			default:
+				BUG_ON(1);
+			}
+		}
+	}
+}
+
+static int64_t cmp_doubles(double l, double r)
+{
+	if (l > r)
+		return -1;
+	else if (l < r)
+		return 1;
+	else
+		return 0;
+}
+
+static int64_t
+__hist_entry__cmp_compute(struct hist_entry *left, struct hist_entry *right,
+			int c)
+{
+	switch (c) {
+	case COMPUTE_DELTA:
+	{
+		double l = left->diff.period_ratio_delta;
+		double r = right->diff.period_ratio_delta;
+
+		return cmp_doubles(l, r);
+	}
+	case COMPUTE_DELTA_ABS:
+	{
+		double l = fabs(left->diff.period_ratio_delta);
+		double r = fabs(right->diff.period_ratio_delta);
+
+		return cmp_doubles(l, r);
+	}
+	case COMPUTE_RATIO:
+	{
+		double l = left->diff.period_ratio;
+		double r = right->diff.period_ratio;
+
+		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);
+	}
+
+	return 0;
+}
+
+static int64_t
+hist_entry__cmp_compute(struct hist_entry *left, struct hist_entry *right,
+			int c, int sort_idx)
+{
+	bool pairs_left  = hist_entry__has_pairs(left);
+	bool pairs_right = hist_entry__has_pairs(right);
+	struct hist_entry *p_right, *p_left;
+
+	if (!pairs_left && !pairs_right)
+		return 0;
+
+	if (!pairs_left || !pairs_right)
+		return pairs_left ? -1 : 1;
+
+	p_left  = get_pair_data(left,  &data__files[sort_idx]);
+	p_right = get_pair_data(right, &data__files[sort_idx]);
+
+	if (!p_left && !p_right)
+		return 0;
+
+	if (!p_left || !p_right)
+		return p_left ? -1 : 1;
+
+	/*
+	 * We have 2 entries of same kind, let's
+	 * make the data comparison.
+	 */
+	return __hist_entry__cmp_compute(p_left, p_right, c);
+}
+
+static int64_t
+hist_entry__cmp_compute_idx(struct hist_entry *left, struct hist_entry *right,
+			    int c, int sort_idx)
+{
+	struct hist_entry *p_right, *p_left;
+
+	p_left  = get_pair_data(left,  &data__files[sort_idx]);
+	p_right = get_pair_data(right, &data__files[sort_idx]);
+
+	if (!p_left && !p_right)
+		return 0;
+
+	if (!p_left || !p_right)
+		return p_left ? -1 : 1;
+
+	if (c != COMPUTE_DELTA && c != COMPUTE_DELTA_ABS) {
+		/*
+		 * The delta can be computed without the baseline, but
+		 * others are not.  Put those entries which have no
+		 * values below.
+		 */
+		if (left->dummy && right->dummy)
+			return 0;
+
+		if (left->dummy || right->dummy)
+			return left->dummy ? 1 : -1;
+	}
+
+	return __hist_entry__cmp_compute(p_left, p_right, c);
+}
+
+static int64_t
+hist_entry__cmp_nop(struct perf_hpp_fmt *fmt __maybe_unused,
+		    struct hist_entry *left __maybe_unused,
+		    struct hist_entry *right __maybe_unused)
+{
+	return 0;
+}
+
+static int64_t
+hist_entry__cmp_baseline(struct perf_hpp_fmt *fmt __maybe_unused,
+			 struct hist_entry *left, struct hist_entry *right)
+{
+	if (left->stat.period == right->stat.period)
+		return 0;
+	return left->stat.period > right->stat.period ? 1 : -1;
+}
+
+static int64_t
+hist_entry__cmp_delta(struct perf_hpp_fmt *fmt,
+		      struct hist_entry *left, struct hist_entry *right)
+{
+	struct data__file *d = fmt_to_data_file(fmt);
+
+	return hist_entry__cmp_compute(right, left, COMPUTE_DELTA, d->idx);
+}
+
+static int64_t
+hist_entry__cmp_delta_abs(struct perf_hpp_fmt *fmt,
+		      struct hist_entry *left, struct hist_entry *right)
+{
+	struct data__file *d = fmt_to_data_file(fmt);
+
+	return hist_entry__cmp_compute(right, left, COMPUTE_DELTA_ABS, d->idx);
+}
+
+static int64_t
+hist_entry__cmp_ratio(struct perf_hpp_fmt *fmt,
+		      struct hist_entry *left, struct hist_entry *right)
+{
+	struct data__file *d = fmt_to_data_file(fmt);
+
+	return hist_entry__cmp_compute(right, left, COMPUTE_RATIO, d->idx);
+}
+
+static int64_t
+hist_entry__cmp_wdiff(struct perf_hpp_fmt *fmt,
+		      struct hist_entry *left, struct hist_entry *right)
+{
+	struct data__file *d = fmt_to_data_file(fmt);
+
+	return hist_entry__cmp_compute(right, left, COMPUTE_WEIGHTED_DIFF, d->idx);
+}
+
+static int64_t
+hist_entry__cmp_delta_idx(struct perf_hpp_fmt *fmt __maybe_unused,
+			  struct hist_entry *left, struct hist_entry *right)
+{
+	return hist_entry__cmp_compute_idx(right, left, COMPUTE_DELTA,
+					   sort_compute);
+}
+
+static int64_t
+hist_entry__cmp_delta_abs_idx(struct perf_hpp_fmt *fmt __maybe_unused,
+			      struct hist_entry *left, struct hist_entry *right)
+{
+	return hist_entry__cmp_compute_idx(right, left, COMPUTE_DELTA_ABS,
+					   sort_compute);
+}
+
+static int64_t
+hist_entry__cmp_ratio_idx(struct perf_hpp_fmt *fmt __maybe_unused,
+			  struct hist_entry *left, struct hist_entry *right)
+{
+	return hist_entry__cmp_compute_idx(right, left, COMPUTE_RATIO,
+					   sort_compute);
+}
+
+static int64_t
+hist_entry__cmp_wdiff_idx(struct perf_hpp_fmt *fmt __maybe_unused,
+			  struct hist_entry *left, struct hist_entry *right)
+{
+	return hist_entry__cmp_compute_idx(right, left, COMPUTE_WEIGHTED_DIFF,
+					   sort_compute);
+}
+
+static void hists__process(struct hists *hists)
+{
+	if (show_baseline_only)
+		hists__baseline_only(hists);
+
+	hists__precompute(hists);
+	hists__output_resort(hists, NULL);
+
+	hists__fprintf(hists, !quiet, 0, 0, 0, stdout,
+		       !symbol_conf.use_callchain);
+}
+
+static void data__fprintf(void)
+{
+	struct data__file *d;
+	int i;
+
+	fprintf(stdout, "# Data files:\n");
+
+	data__for_each_file(i, d)
+		fprintf(stdout, "#  [%d] %s %s\n",
+			d->idx, d->data.file.path,
+			!d->idx ? "(Baseline)" : "");
+
+	fprintf(stdout, "#\n");
+}
+
+static void data_process(void)
+{
+	struct perf_evlist *evlist_base = data__files[0].session->evlist;
+	struct perf_evsel *evsel_base;
+	bool first = true;
+
+	evlist__for_each_entry(evlist_base, evsel_base) {
+		struct hists *hists_base = evsel__hists(evsel_base);
+		struct data__file *d;
+		int i;
+
+		data__for_each_file_new(i, d) {
+			struct perf_evlist *evlist = d->session->evlist;
+			struct perf_evsel *evsel;
+			struct hists *hists;
+
+			evsel = evsel_match(evsel_base, evlist);
+			if (!evsel)
+				continue;
+
+			hists = evsel__hists(evsel);
+			d->hists = hists;
+
+			hists__match(hists_base, hists);
+
+			if (!show_baseline_only)
+				hists__link(hists_base, hists);
+		}
+
+		if (!quiet) {
+			fprintf(stdout, "%s# Event '%s'\n#\n", first ? "" : "\n",
+				perf_evsel__name(evsel_base));
+		}
+
+		first = false;
+
+		if (verbose > 0 || ((data__files_cnt > 2) && !quiet))
+			data__fprintf();
+
+		/* Don't sort callchain for perf diff */
+		perf_evsel__reset_sample_bit(evsel_base, CALLCHAIN);
+
+		hists__process(hists_base);
+	}
+}
+
+static void data__free(struct data__file *d)
+{
+	int col;
+
+	for (col = 0; col < PERF_HPP_DIFF__MAX_INDEX; col++) {
+		struct diff_hpp_fmt *fmt = &d->fmt[col];
+
+		zfree(&fmt->header);
+	}
+}
+
+static int __cmd_diff(void)
+{
+	struct data__file *d;
+	int ret = -EINVAL, i;
+
+	data__for_each_file(i, d) {
+		d->session = perf_session__new(&d->data, false, &tool);
+		if (!d->session) {
+			pr_err("Failed to open %s\n", d->data.file.path);
+			ret = -1;
+			goto out_delete;
+		}
+
+		ret = perf_session__process_events(d->session);
+		if (ret) {
+			pr_err("Failed to process %s\n", d->data.file.path);
+			goto out_delete;
+		}
+
+		perf_evlist__collapse_resort(d->session->evlist);
+	}
+
+	data_process();
+
+ out_delete:
+	data__for_each_file(i, d) {
+		perf_session__delete(d->session);
+		data__free(d);
+	}
+
+	free(data__files);
+	return ret;
+}
+
+static const char * const diff_usage[] = {
+	"perf diff [<options>] [old_file] [new_file]",
+	NULL,
+};
+
+static const struct option options[] = {
+	OPT_INCR('v', "verbose", &verbose,
+		    "be more verbose (show symbol address, etc)"),
+	OPT_BOOLEAN('q', "quiet", &quiet, "Do not show any message"),
+	OPT_BOOLEAN('b', "baseline-only", &show_baseline_only,
+		    "Show only items with match in baseline"),
+	OPT_CALLBACK('c', "compute", &compute,
+		     "delta,delta-abs,ratio,wdiff:w1,w2 (default delta-abs)",
+		     "Entries differential computation selection",
+		     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"),
+	OPT_STRING(0, "kallsyms", &symbol_conf.kallsyms_name,
+		   "file", "kallsyms pathname"),
+	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,
+		    "load module symbols - WARNING: use only with -k and LIVE kernel"),
+	OPT_STRING('d', "dsos", &symbol_conf.dso_list_str, "dso[,dso...]",
+		   "only consider symbols in these dsos"),
+	OPT_STRING('C', "comms", &symbol_conf.comm_list_str, "comm[,comm...]",
+		   "only consider symbols in these comms"),
+	OPT_STRING('S', "symbols", &symbol_conf.sym_list_str, "symbol[,symbol...]",
+		   "only consider these symbols"),
+	OPT_STRING('s', "sort", &sort_order, "key[,key2...]",
+		   "sort by key(s): pid, comm, dso, symbol, parent, cpu, srcline, ..."
+		   " Please refer the man page for the complete list."),
+	OPT_STRING_NOEMPTY('t', "field-separator", &symbol_conf.field_sep, "separator",
+		   "separator for columns, no spaces will be added between "
+		   "columns '.' is reserved."),
+	OPT_CALLBACK(0, "symfs", NULL, "directory",
+		     "Look for files with symbols relative to this directory",
+		     symbol__config_symfs),
+	OPT_UINTEGER('o', "order", &sort_compute, "Specify compute sorting."),
+	OPT_CALLBACK(0, "percentage", NULL, "relative|absolute",
+		     "How to display percentage of filtered entries", parse_filter_percentage),
+	OPT_END()
+};
+
+static double baseline_percent(struct hist_entry *he)
+{
+	u64 total = hists__total_period(he->hists);
+
+	return 100.0 * he->stat.period / total;
+}
+
+static int hpp__color_baseline(struct perf_hpp_fmt *fmt,
+			       struct perf_hpp *hpp, struct hist_entry *he)
+{
+	struct diff_hpp_fmt *dfmt =
+		container_of(fmt, struct diff_hpp_fmt, fmt);
+	double percent = baseline_percent(he);
+	char pfmt[20] = " ";
+
+	if (!he->dummy) {
+		scnprintf(pfmt, 20, "%%%d.2f%%%%", dfmt->header_width - 1);
+		return percent_color_snprintf(hpp->buf, hpp->size,
+					      pfmt, percent);
+	} else
+		return scnprintf(hpp->buf, hpp->size, "%*s",
+				 dfmt->header_width, pfmt);
+}
+
+static int hpp__entry_baseline(struct hist_entry *he, char *buf, size_t size)
+{
+	double percent = baseline_percent(he);
+	const char *fmt = symbol_conf.field_sep ? "%.2f" : "%6.2f%%";
+	int ret = 0;
+
+	if (!he->dummy)
+		ret = scnprintf(buf, size, fmt, percent);
+
+	return ret;
+}
+
+static int __hpp__color_compare(struct perf_hpp_fmt *fmt,
+				struct perf_hpp *hpp, struct hist_entry *he,
+				int comparison_method)
+{
+	struct diff_hpp_fmt *dfmt =
+		container_of(fmt, struct diff_hpp_fmt, fmt);
+	struct hist_entry *pair = get_pair_fmt(he, dfmt);
+	double diff;
+	s64 wdiff;
+	char pfmt[20] = " ";
+
+	if (!pair)
+		goto no_print;
+
+	switch (comparison_method) {
+	case COMPUTE_DELTA:
+		if (pair->diff.computed)
+			diff = pair->diff.period_ratio_delta;
+		else
+			diff = compute_delta(he, pair);
+
+		scnprintf(pfmt, 20, "%%%+d.2f%%%%", dfmt->header_width - 1);
+		return percent_color_snprintf(hpp->buf, hpp->size,
+					pfmt, diff);
+	case COMPUTE_RATIO:
+		if (he->dummy)
+			goto dummy_print;
+		if (pair->diff.computed)
+			diff = pair->diff.period_ratio;
+		else
+			diff = compute_ratio(he, pair);
+
+		scnprintf(pfmt, 20, "%%%d.6f", dfmt->header_width);
+		return value_color_snprintf(hpp->buf, hpp->size,
+					pfmt, diff);
+	case COMPUTE_WEIGHTED_DIFF:
+		if (he->dummy)
+			goto dummy_print;
+		if (pair->diff.computed)
+			wdiff = pair->diff.wdiff;
+		else
+			wdiff = compute_wdiff(he, pair);
+
+		scnprintf(pfmt, 20, "%%14ld", dfmt->header_width);
+		return color_snprintf(hpp->buf, hpp->size,
+				get_percent_color(wdiff),
+				pfmt, wdiff);
+	default:
+		BUG_ON(1);
+	}
+dummy_print:
+	return scnprintf(hpp->buf, hpp->size, "%*s",
+			dfmt->header_width, "N/A");
+no_print:
+	return scnprintf(hpp->buf, hpp->size, "%*s",
+			dfmt->header_width, pfmt);
+}
+
+static int hpp__color_delta(struct perf_hpp_fmt *fmt,
+			struct perf_hpp *hpp, struct hist_entry *he)
+{
+	return __hpp__color_compare(fmt, hpp, he, COMPUTE_DELTA);
+}
+
+static int hpp__color_ratio(struct perf_hpp_fmt *fmt,
+			struct perf_hpp *hpp, struct hist_entry *he)
+{
+	return __hpp__color_compare(fmt, hpp, he, COMPUTE_RATIO);
+}
+
+static int hpp__color_wdiff(struct perf_hpp_fmt *fmt,
+			struct perf_hpp *hpp, struct hist_entry *he)
+{
+	return __hpp__color_compare(fmt, hpp, he, COMPUTE_WEIGHTED_DIFF);
+}
+
+static void
+hpp__entry_unpair(struct hist_entry *he, int idx, char *buf, size_t size)
+{
+	switch (idx) {
+	case PERF_HPP_DIFF__PERIOD_BASELINE:
+		scnprintf(buf, size, "%" PRIu64, he->stat.period);
+		break;
+
+	default:
+		break;
+	}
+}
+
+static void
+hpp__entry_pair(struct hist_entry *he, struct hist_entry *pair,
+		int idx, char *buf, size_t size)
+{
+	double diff;
+	double ratio;
+	s64 wdiff;
+
+	switch (idx) {
+	case PERF_HPP_DIFF__DELTA:
+	case PERF_HPP_DIFF__DELTA_ABS:
+		if (pair->diff.computed)
+			diff = pair->diff.period_ratio_delta;
+		else
+			diff = compute_delta(he, pair);
+
+		scnprintf(buf, size, "%+4.2F%%", diff);
+		break;
+
+	case PERF_HPP_DIFF__RATIO:
+		/* No point for ratio number if we are dummy.. */
+		if (he->dummy) {
+			scnprintf(buf, size, "N/A");
+			break;
+		}
+
+		if (pair->diff.computed)
+			ratio = pair->diff.period_ratio;
+		else
+			ratio = compute_ratio(he, pair);
+
+		if (ratio > 0.0)
+			scnprintf(buf, size, "%14.6F", ratio);
+		break;
+
+	case PERF_HPP_DIFF__WEIGHTED_DIFF:
+		/* No point for wdiff number if we are dummy.. */
+		if (he->dummy) {
+			scnprintf(buf, size, "N/A");
+			break;
+		}
+
+		if (pair->diff.computed)
+			wdiff = pair->diff.wdiff;
+		else
+			wdiff = compute_wdiff(he, pair);
+
+		if (wdiff != 0)
+			scnprintf(buf, size, "%14ld", wdiff);
+		break;
+
+	case PERF_HPP_DIFF__FORMULA:
+		formula_fprintf(he, pair, buf, size);
+		break;
+
+	case PERF_HPP_DIFF__PERIOD:
+		scnprintf(buf, size, "%" PRIu64, pair->stat.period);
+		break;
+
+	default:
+		BUG_ON(1);
+	};
+}
+
+static void
+__hpp__entry_global(struct hist_entry *he, struct diff_hpp_fmt *dfmt,
+		    char *buf, size_t size)
+{
+	struct hist_entry *pair = get_pair_fmt(he, dfmt);
+	int idx = dfmt->idx;
+
+	/* baseline is special */
+	if (idx == PERF_HPP_DIFF__BASELINE)
+		hpp__entry_baseline(he, buf, size);
+	else {
+		if (pair)
+			hpp__entry_pair(he, pair, idx, buf, size);
+		else
+			hpp__entry_unpair(he, idx, buf, size);
+	}
+}
+
+static int hpp__entry_global(struct perf_hpp_fmt *_fmt, struct perf_hpp *hpp,
+			     struct hist_entry *he)
+{
+	struct diff_hpp_fmt *dfmt =
+		container_of(_fmt, struct diff_hpp_fmt, fmt);
+	char 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);
+	else
+		return scnprintf(hpp->buf, hpp->size, "%*s",
+				 dfmt->header_width, buf);
+}
+
+static int hpp__header(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp,
+		       struct hists *hists __maybe_unused,
+		       int line __maybe_unused,
+		       int *span __maybe_unused)
+{
+	struct diff_hpp_fmt *dfmt =
+		container_of(fmt, struct diff_hpp_fmt, fmt);
+
+	BUG_ON(!dfmt->header);
+	return scnprintf(hpp->buf, hpp->size, dfmt->header);
+}
+
+static int hpp__width(struct perf_hpp_fmt *fmt,
+		      struct perf_hpp *hpp __maybe_unused,
+		      struct hists *hists __maybe_unused)
+{
+	struct diff_hpp_fmt *dfmt =
+		container_of(fmt, struct diff_hpp_fmt, fmt);
+
+	BUG_ON(dfmt->header_width <= 0);
+	return dfmt->header_width;
+}
+
+static void init_header(struct data__file *d, struct diff_hpp_fmt *dfmt)
+{
+#define MAX_HEADER_NAME 100
+	char buf_indent[MAX_HEADER_NAME];
+	char buf[MAX_HEADER_NAME];
+	const char *header = NULL;
+	int width = 0;
+
+	BUG_ON(dfmt->idx >= PERF_HPP_DIFF__MAX_INDEX);
+	header = columns[dfmt->idx].name;
+	width  = columns[dfmt->idx].width;
+
+	/* 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);
+	if (dfmt->header_width < width)
+		dfmt->header_width = width;
+
+	scnprintf(buf_indent, MAX_HEADER_NAME, "%*s",
+		  dfmt->header_width, NAME);
+
+	dfmt->header = strdup(buf_indent);
+#undef MAX_HEADER_NAME
+#undef NAME
+}
+
+static void data__hpp_register(struct data__file *d, int idx)
+{
+	struct diff_hpp_fmt *dfmt = &d->fmt[idx];
+	struct perf_hpp_fmt *fmt = &dfmt->fmt;
+
+	dfmt->idx = idx;
+
+	fmt->header = hpp__header;
+	fmt->width  = hpp__width;
+	fmt->entry  = hpp__entry_global;
+	fmt->cmp    = hist_entry__cmp_nop;
+	fmt->collapse = hist_entry__cmp_nop;
+
+	/* TODO more colors */
+	switch (idx) {
+	case PERF_HPP_DIFF__BASELINE:
+		fmt->color = hpp__color_baseline;
+		fmt->sort  = hist_entry__cmp_baseline;
+		break;
+	case PERF_HPP_DIFF__DELTA:
+		fmt->color = hpp__color_delta;
+		fmt->sort  = hist_entry__cmp_delta;
+		break;
+	case PERF_HPP_DIFF__RATIO:
+		fmt->color = hpp__color_ratio;
+		fmt->sort  = hist_entry__cmp_ratio;
+		break;
+	case PERF_HPP_DIFF__WEIGHTED_DIFF:
+		fmt->color = hpp__color_wdiff;
+		fmt->sort  = hist_entry__cmp_wdiff;
+		break;
+	case PERF_HPP_DIFF__DELTA_ABS:
+		fmt->color = hpp__color_delta;
+		fmt->sort  = hist_entry__cmp_delta_abs;
+		break;
+	default:
+		fmt->sort  = hist_entry__cmp_nop;
+		break;
+	}
+
+	init_header(d, dfmt);
+	perf_hpp__column_register(fmt);
+	perf_hpp__register_sort_field(fmt);
+}
+
+static int ui_init(void)
+{
+	struct data__file *d;
+	struct perf_hpp_fmt *fmt;
+	int i;
+
+	data__for_each_file(i, d) {
+
+		/*
+		 * Baseline or compute realted columns:
+		 *
+		 *   PERF_HPP_DIFF__BASELINE
+		 *   PERF_HPP_DIFF__DELTA
+		 *   PERF_HPP_DIFF__RATIO
+		 *   PERF_HPP_DIFF__WEIGHTED_DIFF
+		 */
+		data__hpp_register(d, i ? compute_2_hpp[compute] :
+					  PERF_HPP_DIFF__BASELINE);
+
+		/*
+		 * And the rest:
+		 *
+		 * PERF_HPP_DIFF__FORMULA
+		 * PERF_HPP_DIFF__PERIOD
+		 * PERF_HPP_DIFF__PERIOD_BASELINE
+		 */
+		if (show_formula && i)
+			data__hpp_register(d, PERF_HPP_DIFF__FORMULA);
+
+		if (show_period)
+			data__hpp_register(d, i ? PERF_HPP_DIFF__PERIOD :
+						  PERF_HPP_DIFF__PERIOD_BASELINE);
+	}
+
+	if (!sort_compute)
+		return 0;
+
+	/*
+	 * Prepend an fmt to sort on columns at 'sort_compute' first.
+	 * This fmt is added only to the sort list but not to the
+	 * output fields list.
+	 *
+	 * Note that this column (data) can be compared twice - one
+	 * for this 'sort_compute' fmt and another for the normal
+	 * diff_hpp_fmt.  But it shouldn't a problem as most entries
+	 * will be sorted out by first try or baseline and comparing
+	 * is not a costly operation.
+	 */
+	fmt = zalloc(sizeof(*fmt));
+	if (fmt == NULL) {
+		pr_err("Memory allocation failed\n");
+		return -1;
+	}
+
+	fmt->cmp      = hist_entry__cmp_nop;
+	fmt->collapse = hist_entry__cmp_nop;
+
+	switch (compute) {
+	case COMPUTE_DELTA:
+		fmt->sort = hist_entry__cmp_delta_idx;
+		break;
+	case COMPUTE_RATIO:
+		fmt->sort = hist_entry__cmp_ratio_idx;
+		break;
+	case COMPUTE_WEIGHTED_DIFF:
+		fmt->sort = hist_entry__cmp_wdiff_idx;
+		break;
+	case COMPUTE_DELTA_ABS:
+		fmt->sort = hist_entry__cmp_delta_abs_idx;
+		break;
+	default:
+		BUG_ON(1);
+	}
+
+	perf_hpp__prepend_sort_field(fmt);
+	return 0;
+}
+
+static int data_init(int argc, const char **argv)
+{
+	struct data__file *d;
+	static const char *defaults[] = {
+		"perf.data.old",
+		"perf.data",
+	};
+	bool use_default = true;
+	int i;
+
+	data__files_cnt = 2;
+
+	if (argc) {
+		if (argc == 1)
+			defaults[1] = argv[0];
+		else {
+			data__files_cnt = argc;
+			use_default = false;
+		}
+	} else if (perf_guest) {
+		defaults[0] = "perf.data.host";
+		defaults[1] = "perf.data.guest";
+	}
+
+	if (sort_compute >= (unsigned int) data__files_cnt) {
+		pr_err("Order option out of limit.\n");
+		return -EINVAL;
+	}
+
+	data__files = zalloc(sizeof(*data__files) * data__files_cnt);
+	if (!data__files)
+		return -ENOMEM;
+
+	data__for_each_file(i, d) {
+		struct perf_data *data = &d->data;
+
+		data->file.path = use_default ? defaults[i] : argv[i];
+		data->mode      = PERF_DATA_MODE_READ,
+		data->force     = force,
+
+		d->idx  = i;
+	}
+
+	return 0;
+}
+
+static int diff__config(const char *var, const char *value,
+			void *cb __maybe_unused)
+{
+	if (!strcmp(var, "diff.order")) {
+		int ret;
+		if (perf_config_int(&ret, var, value) < 0)
+			return -1;
+		sort_compute = ret;
+		return 0;
+	}
+	if (!strcmp(var, "diff.compute")) {
+		if (!strcmp(value, "delta")) {
+			compute = COMPUTE_DELTA;
+		} else if (!strcmp(value, "delta-abs")) {
+			compute = COMPUTE_DELTA_ABS;
+		} else if (!strcmp(value, "ratio")) {
+			compute = COMPUTE_RATIO;
+		} else if (!strcmp(value, "wdiff")) {
+			compute = COMPUTE_WEIGHTED_DIFF;
+		} else {
+			pr_err("Invalid compute method: %s\n", value);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+int cmd_diff(int argc, const char **argv)
+{
+	int ret = hists__init();
+
+	if (ret < 0)
+		return ret;
+
+	perf_config(diff__config, NULL);
+
+	argc = parse_options(argc, argv, options, diff_usage, 0);
+
+	if (quiet)
+		perf_quiet_option();
+
+	if (symbol__init(NULL) < 0)
+		return -1;
+
+	if (data_init(argc, argv) < 0)
+		return -1;
+
+	if (ui_init() < 0)
+		return -1;
+
+	sort__mode = SORT_MODE__DIFF;
+
+	if (setup_sorting(NULL) < 0)
+		usage_with_options(diff_usage, options);
+
+	setup_pager();
+
+	sort__setup_elide(NULL);
+
+	return __cmd_diff();
+}