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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: Anton Blanchard <anton@samba.org>
Signed-off-by: Sukadev 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Sukadev Bhattiprolu 2014-10-21 17:09:58 -07:00 committed by Arnaldo Carvalho de Melo
parent 4cdcc33db2
commit 7d073b335e
2 changed files with 23 additions and 11 deletions

View File

@ -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;
@ -156,15 +156,27 @@ static int check_return_addr(const char *exec_file, Dwarf_Addr pc)
Dwarf_Addr end = pc;
bool signalp;
dwfl = dwfl_begin(&offline_callbacks);
if (!dwfl) {
pr_debug("dwfl_begin() failed: %s\n", dwarf_errmsg(-1));
return -1;
}
dwfl = dso->dwfl;
if (dwfl_report_offline(dwfl, "", exec_file, -1) == NULL) {
pr_debug("dwfl_report_offline() failed %s\n", dwarf_errmsg(-1));
goto out;
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, "", 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);
@ -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);

View File

@ -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 {