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Commit 7737af01 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
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perf probe: Speed up perf probe --list by caching debuginfo 



Speed up the "perf probe --list" by caching the last used debuginfo.
perf probe --list always open and load debuginfo for each entry of probe
list. This takes very a long time.

E.g. with vfs_* events (total 96 probes)

  [root@localhost perf]# time  ./perf probe -l &> /dev/null

  real    0m25.376s
  user    0m24.381s
  sys     0m1.012s

To solve this issue, this adds debuginfo_cache to cache the
last used debuginfo on memory.

With this fix, the perf-probe --list significantly improves
its speed.

  [root@localhost perf]#  time  ./perf probe -l &> /dev/null

  real    0m0.161s
  user    0m0.136s
  sys     0m0.025s

Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naohiro Aota <naota@elisp.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20150617145854.19715.15314.stgit@localhost.localdomain


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent d350bd57

tools/perf/util/probe-event.c

+44 −4
Original line number Diff line number Diff line
@@ -429,6 +429,41 @@ static struct debuginfo *open_debuginfo(const char *module, bool silent) 
	return ret;

}



/* For caching the last debuginfo */

static struct debuginfo *debuginfo_cache;

static char *debuginfo_cache_path;



static struct debuginfo *debuginfo_cache__open(const char *module, bool silent)

{

	if ((debuginfo_cache_path && !strcmp(debuginfo_cache_path, module)) ||

	    (!debuginfo_cache_path && !module && debuginfo_cache))

		goto out;



	/* Copy module path */

	free(debuginfo_cache_path);

	if (module) {

		debuginfo_cache_path = strdup(module);

		if (!debuginfo_cache_path) {

			debuginfo__delete(debuginfo_cache);

			debuginfo_cache = NULL;

			goto out;

		}

	}



	debuginfo_cache = open_debuginfo(module, silent);

	if (!debuginfo_cache)

		zfree(&debuginfo_cache_path);

out:

	return debuginfo_cache;

}



static void debuginfo_cache__exit(void)

{

	debuginfo__delete(debuginfo_cache);

	debuginfo_cache = NULL;

	zfree(&debuginfo_cache_path);

}





static int get_text_start_address(const char *exec, unsigned long *address)

{
@@ -490,12 +525,11 @@ static int find_perf_probe_point_from_dwarf(struct probe_trace_point *tp, 
	pr_debug("try to find information at %" PRIx64 " in %s\n", addr,

		 tp->module ? : "kernel");



	dinfo = open_debuginfo(tp->module, verbose == 0);

	if (dinfo) {

	dinfo = debuginfo_cache__open(tp->module, verbose == 0);

	if (dinfo)

		ret = debuginfo__find_probe_point(dinfo,

						 (unsigned long)addr, pp);

		debuginfo__delete(dinfo);

	} else

	else

		ret = -ENOENT;



	if (ret > 0) {
@@ -930,6 +964,10 @@ int show_available_vars(struct perf_probe_event *pevs, int npevs, 


#else	/* !HAVE_DWARF_SUPPORT */



static void debuginfo_cache__exit(void)

{

}



static int

find_perf_probe_point_from_dwarf(struct probe_trace_point *tp __maybe_unused,

				 struct perf_probe_point *pp __maybe_unused,
@@ -2266,6 +2304,8 @@ static int __show_perf_probe_events(int fd, bool is_kprobe, 
			break;

	}

	strlist__delete(rawlist);

	/* Cleanup cached debuginfo if needed */

	debuginfo_cache__exit();



	return ret;

}