perf diff: Introduce tool to show performance difference

perf-diff(1)

==============

NAME

----

perf-diff - Read perf.data (created by perf record) and display the profile

SYNOPSIS

--------

[verse]

'perf diff' [oldfile] [newfile]

DESCRIPTION

-----------

This command displays the performance difference among two perf.data files

captured via perf record.

If no parameters are passed it will assume perf.data.old and perf.data.

OPTIONS

-------

-p::

--percentage::

	Show percentages instead of raw counters

-v::

--verbose::

	Be verbose, for instance, show the raw counters in addition to the

	diff.

SEE ALSO

--------

linkperf:perf-record[1]

BUILTIN_OBJS += bench/sched-pipe.o

BUILTIN_OBJS += bench/mem-memcpy.o

BUILTIN_OBJS += builtin-diff.o

BUILTIN_OBJS += builtin-help.o

BUILTIN_OBJS += builtin-sched.o

BUILTIN_OBJS += builtin-buildid-list.o

/*

 * 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/session.h"

#include "util/sort.h"

#include "util/symbol.h"

#include "util/util.h"

#include <stdlib.h>

static char	   const *input_old = "perf.data.old",

			 *input_new = "perf.data";

static int	   force;

static bool 	   show_percent;

struct symbol_conf symbol_conf;

static int perf_session__add_hist_entry(struct perf_session *self,

					struct addr_location *al, u64 count)

{

	bool hit;

	struct hist_entry *he = __perf_session__add_hist_entry(self, al, NULL,

							       count, &hit);

	if (he == NULL)

		return -ENOMEM;

	if (hit)

		he->count += count;

	return 0;

}

static int diff__process_sample_event(event_t *event, struct perf_session *session)

{

	struct addr_location al;

	struct sample_data data = { .period = 1, };

	dump_printf("(IP, %d): %d: %p\n", event->header.misc,

		    event->ip.pid, (void *)(long)event->ip.ip);

	if (event__preprocess_sample(event, session, &al, NULL) < 0) {

		pr_warning("problem processing %d event, skipping it.\n",

			   event->header.type);

		return -1;

	}

	event__parse_sample(event, session->sample_type, &data);

	if (al.sym && perf_session__add_hist_entry(session, &al, data.period)) {

		pr_warning("problem incrementing symbol count, skipping event\n");

		return -1;

	}

	session->events_stats.total += data.period;

	return 0;

}

static struct perf_event_ops event_ops = {

	.process_sample_event = diff__process_sample_event,

	.process_mmap_event   = event__process_mmap,

	.process_comm_event   = event__process_comm,

	.process_exit_event   = event__process_task,

	.process_fork_event   = event__process_task,

	.process_lost_event   = event__process_lost,

};

static void perf_session__insert_hist_entry_by_name(struct rb_root *root,

						    struct hist_entry *he)

{

	struct rb_node **p = &root->rb_node;

	struct rb_node *parent = NULL;

	struct hist_entry *iter;

	while (*p != NULL) {

		int cmp;

		parent = *p;

		iter = rb_entry(parent, struct hist_entry, rb_node);

		cmp = strcmp(he->map->dso->name, iter->map->dso->name);

		if (cmp > 0)

			p = &(*p)->rb_left;

		else if (cmp < 0)

			p = &(*p)->rb_right;

		else {

			cmp = strcmp(he->sym->name, iter->sym->name);

			if (cmp > 0)

				p = &(*p)->rb_left;

			else

				p = &(*p)->rb_right;

		}

	}

	rb_link_node(&he->rb_node, parent, p);

	rb_insert_color(&he->rb_node, root);

}

static void perf_session__resort_by_name(struct perf_session *self)

{

	unsigned long position = 1;

	struct rb_root tmp = RB_ROOT;

	struct rb_node *next = rb_first(&self->hists);

	while (next != NULL) {

		struct hist_entry *n = rb_entry(next, struct hist_entry, rb_node);

		next = rb_next(&n->rb_node);

		rb_erase(&n->rb_node, &self->hists);

		n->position = position++;

		perf_session__insert_hist_entry_by_name(&tmp, n);

	}

	self->hists = tmp;

}

static struct hist_entry *

perf_session__find_hist_entry_by_name(struct perf_session *self,

				      struct hist_entry *he)

{

	struct rb_node *n = self->hists.rb_node;

	while (n) {

		struct hist_entry *iter = rb_entry(n, struct hist_entry, rb_node);

		int cmp = strcmp(he->map->dso->name, iter->map->dso->name);

		if (cmp > 0)

			n = n->rb_left;

		else if (cmp < 0)

			n = n->rb_right;

		else {

			cmp = strcmp(he->sym->name, iter->sym->name);

			if (cmp > 0)

				n = n->rb_left;

			else if (cmp < 0)

				n = n->rb_right;

			else

				return iter;

		}

	}

	return NULL;

}

static void perf_session__match_hists(struct perf_session *old_session,

				      struct perf_session *new_session)

{

	struct rb_node *nd;

	perf_session__resort_by_name(old_session);

	for (nd = rb_first(&new_session->hists); nd; nd = rb_next(nd)) {

		struct hist_entry *pos = rb_entry(nd, struct hist_entry, rb_node);

		pos->pair = perf_session__find_hist_entry_by_name(old_session, pos);

	}

}

static size_t hist_entry__fprintf_matched(struct hist_entry *self,

					  unsigned long pos,

					  struct perf_session *session,

					  struct perf_session *pair_session,

					  FILE *fp)

{

	u64 old_count = 0;

	char displacement[16];

	size_t printed;

	if (self->pair != NULL) {

		long pdiff = (long)self->pair->position - (long)pos;

		old_count = self->pair->count;

		if (pdiff == 0)

			goto blank;

		snprintf(displacement, sizeof(displacement), "%+4ld", pdiff);

	} else {

blank:		memset(displacement, ' ', sizeof(displacement));

	}

	printed = fprintf(fp, "%4lu %5.5s ", pos, displacement);

	if (show_percent) {

		double old_percent = (old_count * 100) / pair_session->events_stats.total,

		       new_percent = (self->count * 100) / session->events_stats.total;

		double diff = old_percent - new_percent;

		if (verbose)

			printed += fprintf(fp, " %3.2f%% %3.2f%%", old_percent, new_percent);

		if ((u64)diff != 0)

			printed += fprintf(fp, " %+4.2F%%", diff);

		else

			printed += fprintf(fp, "       ");

	} else {

		if (verbose)

			printed += fprintf(fp, " %9Lu %9Lu", old_count, self->count);

		printed += fprintf(fp, " %+9Ld", (s64)self->count - (s64)old_count);

	}

	return printed + fprintf(fp, " %25.25s   %s\n",

				 self->map->dso->name, self->sym->name);

}

static size_t perf_session__fprintf_matched_hists(struct perf_session *self,

						  struct perf_session *pair,

						  FILE *fp)

{

	struct rb_node *nd;

	size_t printed = 0;

	unsigned long pos = 1;

	for (nd = rb_first(&self->hists); nd; nd = rb_next(nd)) {

		struct hist_entry *he = rb_entry(nd, struct hist_entry, rb_node);

		printed += hist_entry__fprintf_matched(he, pos++, self, pair, fp);

	}

	return printed;

}

static int __cmd_diff(void)

{

	int ret, i;

	struct perf_session *session[2];

	session[0] = perf_session__new(input_old, O_RDONLY, force, &symbol_conf);

	session[1] = perf_session__new(input_new, O_RDONLY, force, &symbol_conf);

	if (session[0] == NULL || session[1] == NULL)

		return -ENOMEM;

	for (i = 0; i < 2; ++i) {

		ret = perf_session__process_events(session[i], &event_ops);

		if (ret)

			goto out_delete;

		perf_session__output_resort(session[i], session[i]->events_stats.total);

	}

	perf_session__match_hists(session[0], session[1]);

	perf_session__fprintf_matched_hists(session[1], session[0], stdout);

out_delete:

	for (i = 0; i < 2; ++i)

		perf_session__delete(session[i]);

	return ret;

}

static const char *const diff_usage[] = {

	"perf diff [<options>] [old_file] [new_file]",

};

static const struct option options[] = {

	OPT_BOOLEAN('v', "verbose", &verbose,

		    "be more verbose (show symbol address, etc)"),

	OPT_BOOLEAN('D', "dump-raw-trace", &dump_trace,

		    "dump raw trace in ASCII"),

	OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),

	OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules,

		    "load module symbols - WARNING: use only with -k and LIVE kernel"),

	OPT_BOOLEAN('p', "percentages", &show_percent,

		    "Don't shorten the pathnames taking into account the cwd"),

	OPT_BOOLEAN('P', "full-paths", &event_ops.full_paths,

		    "Don't shorten the pathnames taking into account the cwd"),

	OPT_END()

};

int cmd_diff(int argc, const char **argv, const char *prefix __used)

{

	if (symbol__init(&symbol_conf) < 0)

		return -1;

	setup_sorting(diff_usage, options);

	argc = parse_options(argc, argv, options, diff_usage, 0);

	if (argc) {

		if (argc > 2)

			usage_with_options(diff_usage, options);

		if (argc == 2) {

			input_old = argv[0];

			input_new = argv[1];

		} else

			input_new = argv[0];

	}

	setup_pager();

	return __cmd_diff();

}

extern int cmd_annotate(int argc, const char **argv, const char *prefix);

extern int cmd_bench(int argc, const char **argv, const char *prefix);

extern int cmd_buildid_list(int argc, const char **argv, const char *prefix);

extern int cmd_diff(int argc, const char **argv, const char *prefix);

extern int cmd_help(int argc, const char **argv, const char *prefix);

extern int cmd_sched(int argc, const char **argv, const char *prefix);

extern int cmd_list(int argc, const char **argv, const char *prefix);

perf-annotate			mainporcelain common

perf-bench			mainporcelain common

perf-buildid-list		mainporcelain common

perf-diff			mainporcelain common

perf-list			mainporcelain common

perf-sched			mainporcelain common

perf-record			mainporcelain common