Commit 7d073b33 authored by Sukadev Bhattiprolu's avatar Sukadev Bhattiprolu Committed by Arnaldo Carvalho de Melo
Browse files

perf tools powerpc: Cache the DWARF debug info 



Cache the DWARF debug info for DSO so we don't have to rebuild it for each
address in the DSO.

Note that dso__new() uses calloc() so don't need to set dso->dwfl to NULL.

	$ /tmp/perf.orig --version
	perf version 3.18.rc1.gc2661b8
	$ /tmp/perf.new --version
	perf version 3.18.rc1.g402d62
	$ perf stat -e cycles,instructions /tmp/perf.orig report -g > orig

	 Performance counter stats for '/tmp/perf.orig report -g':

	     6,428,177,183 cycles                    #    0.000 GHz
	     4,176,288,391 instructions              #    0.65  insns per cycle

	       1.840666132 seconds time elapsed

	$ perf stat -e cycles,instructions /tmp/perf.new report -g > new

	 Performance counter stats for '/tmp/perf.new report -g':

	       305,773,142 cycles                    #    0.000 GHz
	       276,048,272 instructions              #    0.90  insns per cycle

	       0.087693543 seconds time elapsed
	$ diff orig new
	$

Changelog[v2]:

[Arnaldo Carvalho] Cache in existing global objects rather than create
                   new static/globals in functions.

Reported-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Anton Blanchard <anton@au1.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20141022000958.GB2228@us.ibm.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 4cdcc33d

tools/perf/arch/powerpc/util/skip-callchain-idx.c

+22 −11
Original line number Diff line number Diff line
@@ -145,7 +145,7 @@ static Dwarf_Frame *get_dwarf_frame(Dwfl_Module *mod, Dwarf_Addr pc) 
 *		yet used)

 *	-1 in case of errors

 */

static int check_return_addr(const char *exec_file, Dwarf_Addr pc)

static int check_return_addr(struct dso *dso, Dwarf_Addr pc)

{

	int		rc = -1;

	Dwfl		*dwfl;
@@ -156,16 +156,28 @@ static int check_return_addr(const char *exec_file, Dwarf_Addr pc) 
	Dwarf_Addr	end = pc;

	bool		signalp;



	dwfl = dso->dwfl;



	if (!dwfl) {

		dwfl = dwfl_begin(&offline_callbacks);

		if (!dwfl) {

			pr_debug("dwfl_begin() failed: %s\n", dwarf_errmsg(-1));

			return -1;

		}



	if (dwfl_report_offline(dwfl, "",  exec_file, -1) == NULL) {

		pr_debug("dwfl_report_offline() failed %s\n", dwarf_errmsg(-1));

		if (dwfl_report_offline(dwfl, "", dso->long_name, -1) == NULL) {

			pr_debug("dwfl_report_offline() failed %s\n",

						dwarf_errmsg(-1));

			/*

			 * We normally cache the DWARF debug info and never

			 * call dwfl_end(). But to prevent fd leak, free in

			 * case of error.

			 */

			dwfl_end(dwfl);

			goto out;

		}

		dso->dwfl = dwfl;

	}



	mod = dwfl_addrmodule(dwfl, pc);

	if (!mod) {
@@ -194,7 +206,6 @@ static int check_return_addr(const char *exec_file, Dwarf_Addr pc) 
	rc = check_return_reg(ra_regno, frame);



out:

	dwfl_end(dwfl);

	return rc;

}
@@ -246,7 +257,7 @@ int arch_skip_callchain_idx(struct machine *machine, struct thread *thread, 
		return skip_slot;

	}



	rc = check_return_addr(dso->long_name, ip);

	rc = check_return_addr(dso, ip);



	pr_debug("DSO %s, nr %" PRIx64 ", ip 0x%" PRIx64 "rc %d\n",

				dso->long_name, chain->nr, ip, rc);

tools/perf/util/dso.h

+1 −0
Original line number Diff line number Diff line
@@ -127,6 +127,7 @@ struct dso { 
	const char	 *long_name;

	u16		 long_name_len;

	u16		 short_name_len;

	void		*dwfl;			/* DWARF debug info */



	/* dso data file */

	struct {

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