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Commit 26d33022 authored by Jiri Olsa's avatar Jiri Olsa Committed by Arnaldo Carvalho de Melo
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perf tools: Support for DWARF mode callchain 



This patch enables perf to use the DWARF unwind code.

It extends the perf record '-g' option with following arguments:
  'fp'           - provides framepointer based user
                   stack backtrace
  'dwarf[,size]' - provides DWARF (libunwind) based user stack
                   backtrace. The size specifies the size of the
                   user stack dump. If omitted it is 8192 by default.

If libunwind is found during the perf build, then the 'dwarf' argument
becomes available for record command. The 'fp' stays as default option
in any case.

Examples: (perf compiled with libunwind)

   perf record -g dwarf ls
      - provides dwarf unwind with 8192 as stack dump size

   perf record -g dwarf,4096 ls
      - provides dwarf unwind with 4096 as stack dump size

   perf record -g -- ls
   perf record -g fp ls
      - provides frame pointer unwind

Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
Original-patch-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Benjamin Redelings <benjamin.redelings@nescent.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/1344345647-11536-13-git-send-email-jolsa@redhat.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 71ad0f5e

tools/perf/builtin-record.c

+112 −2
Original line number Diff line number Diff line
@@ -31,6 +31,15 @@ 
#include <sched.h>

#include <sys/mman.h>



#define CALLCHAIN_HELP "do call-graph (stack chain/backtrace) recording: "



#ifdef NO_LIBUNWIND_SUPPORT

static char callchain_help[] = CALLCHAIN_HELP "[fp]";

#else

static unsigned long default_stack_dump_size = 8192;

static char callchain_help[] = CALLCHAIN_HELP "[fp] dwarf";

#endif



enum write_mode_t {

	WRITE_FORCE,

	WRITE_APPEND
@@ -732,6 +741,106 @@ parse_branch_stack(const struct option *opt, const char *str, int unset) 
	return ret;

}



#ifndef NO_LIBUNWIND_SUPPORT

static int get_stack_size(char *str, unsigned long *_size)

{

	char *endptr;

	unsigned long size;

	unsigned long max_size = round_down(USHRT_MAX, sizeof(u64));



	size = strtoul(str, &endptr, 0);



	do {

		if (*endptr)

			break;



		size = round_up(size, sizeof(u64));

		if (!size || size > max_size)

			break;



		*_size = size;

		return 0;



	} while (0);



	pr_err("callchain: Incorrect stack dump size (max %ld): %s\n",

	       max_size, str);

	return -1;

}

#endif /* !NO_LIBUNWIND_SUPPORT */



static int

parse_callchain_opt(const struct option *opt __used, const char *arg,

		    int unset)

{

	struct perf_record *rec = (struct perf_record *)opt->value;

	char *tok, *name, *saveptr = NULL;

	char *buf;

	int ret = -1;



	/* --no-call-graph */

	if (unset)

		return 0;



	/* We specified default option if none is provided. */

	BUG_ON(!arg);



	/* We need buffer that we know we can write to. */

	buf = malloc(strlen(arg) + 1);

	if (!buf)

		return -ENOMEM;



	strcpy(buf, arg);



	tok = strtok_r((char *)buf, ",", &saveptr);

	name = tok ? : (char *)buf;



	do {

		/* Framepointer style */

		if (!strncmp(name, "fp", sizeof("fp"))) {

			if (!strtok_r(NULL, ",", &saveptr)) {

				rec->opts.call_graph = CALLCHAIN_FP;

				ret = 0;

			} else

				pr_err("callchain: No more arguments "

				       "needed for -g fp\n");

			break;



#ifndef NO_LIBUNWIND_SUPPORT

		/* Dwarf style */

		} else if (!strncmp(name, "dwarf", sizeof("dwarf"))) {

			ret = 0;

			rec->opts.call_graph = CALLCHAIN_DWARF;

			rec->opts.stack_dump_size = default_stack_dump_size;



			tok = strtok_r(NULL, ",", &saveptr);

			if (tok) {

				unsigned long size = 0;



				ret = get_stack_size(tok, &size);

				rec->opts.stack_dump_size = size;

			}



			if (!ret)

				pr_debug("callchain: stack dump size %d\n",

					 rec->opts.stack_dump_size);

#endif /* !NO_LIBUNWIND_SUPPORT */

		} else {

			pr_err("callchain: Unknown -g option "

			       "value: %s\n", arg);

			break;

		}



	} while (0);



	free(buf);



	if (!ret)

		pr_debug("callchain: type %d\n", rec->opts.call_graph);



	return ret;

}



static const char * const record_usage[] = {

	"perf record [<options>] [<command>]",

	"perf record [<options>] -- <command> [<options>]",
@@ -803,8 +912,9 @@ const struct option record_options[] = { 
		     "number of mmap data pages"),

	OPT_BOOLEAN(0, "group", &record.opts.group,

		    "put the counters into a counter group"),

	OPT_BOOLEAN('g', "call-graph", &record.opts.call_graph,

		    "do call-graph (stack chain/backtrace) recording"),

	OPT_CALLBACK_DEFAULT('g', "call-graph", &record, "mode[,dump_size]",

			     callchain_help, &parse_callchain_opt,

			     "fp"),

	OPT_INCR('v', "verbose", &verbose,

		    "be more verbose (show counter open errors, etc)"),

	OPT_BOOLEAN('q', "quiet", &quiet, "don't print any message"),

tools/perf/perf.h

+8 −1
Original line number Diff line number Diff line
@@ -209,9 +209,15 @@ void pthread__unblock_sigwinch(void); 


#include "util/target.h"



enum perf_call_graph_mode {

	CALLCHAIN_NONE,

	CALLCHAIN_FP,

	CALLCHAIN_DWARF

};



struct perf_record_opts {

	struct perf_target target;

	bool	     call_graph;

	int	     call_graph;

	bool	     group;

	bool	     inherit_stat;

	bool	     no_delay;
@@ -230,6 +236,7 @@ struct perf_record_opts { 
	u64          branch_stack;

	u64	     default_interval;

	u64	     user_interval;

	u16	     stack_dump_size;

};



#endif

tools/perf/util/evsel.c

+12 −1
Original line number Diff line number Diff line
@@ -17,6 +17,8 @@ 
#include "thread_map.h"

#include "target.h"

#include "../../../include/linux/hw_breakpoint.h"

#include "../../include/linux/perf_event.h"

#include "perf_regs.h"



#define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))

#define GROUP_FD(group_fd, cpu) (*(int *)xyarray__entry(group_fd, cpu, 0))
@@ -368,9 +370,18 @@ void perf_evsel__config(struct perf_evsel *evsel, struct perf_record_opts *opts, 
		attr->mmap_data = track;

	}



	if (opts->call_graph)

	if (opts->call_graph) {

		attr->sample_type	|= PERF_SAMPLE_CALLCHAIN;



		if (opts->call_graph == CALLCHAIN_DWARF) {

			attr->sample_type |= PERF_SAMPLE_REGS_USER |

					     PERF_SAMPLE_STACK_USER;

			attr->sample_regs_user = PERF_REGS_MASK;

			attr->sample_stack_user = opts->stack_dump_size;

			attr->exclude_callchain_user = 1;

		}

	}



	if (perf_target__has_cpu(&opts->target))

		attr->sample_type	|= PERF_SAMPLE_CPU;