summaryrefslogtreecommitdiffstats
path: root/tools
diff options
context:
space:
mode:
authorLin Ming <ming.m.lin@intel.com>2011-03-25 09:27:48 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2011-03-29 18:40:27 +0200
commitcd25f8bc2696664877b21d33b7994e12fa570919 (patch)
tree13c56bdc4f248d76804fc703a44b79887cfba159 /tools
parentperf tools: Emit clearer message for sys_perf_event_open ENOENT return (diff)
downloadlinux-cd25f8bc2696664877b21d33b7994e12fa570919.tar.xz
linux-cd25f8bc2696664877b21d33b7994e12fa570919.zip
perf probe: Add fastpath to do lookup by function name
v3 -> v2: - Make pubname_search_cb more generic - Add fastpath to find_probes also v2 -> v1: - Don't compare file names with cu_find_realpath(...), instead, compare them with the name returned by dwarf_decl_file(sp_die) The vmlinux file may have thousands of CUs. We can lookup function name from .debug_pubnames section to avoid the slow loop on CUs. 1. Improvement data for find_line_range ./perf stat -e cycles -r 10 -- ./perf probe -k /home/mlin/vmlinux \ -s /home/mlin/linux-2.6 \ --line csum_partial_copy_to_user > tmp.log before patch applied ===================== 847,988,276 cycles 0.355075856 seconds time elapsed after patch applied ===================== 206,102,622 cycles 0.086883555 seconds time elapsed 2. Improvement data for find_probes ./perf stat -e cycles -r 10 -- ./perf probe -k /home/mlin/vmlinux \ -s /home/mlin/linux-2.6 \ --vars csum_partial_copy_to_user > tmp.log before patch applied ===================== 848,490,844 cycles 0.355307901 seconds time elapsed after patch applied ===================== 205,684,469 cycles 0.086694010 seconds time elapsed Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: linux-kernel <linux-kernel@vger.kernel.org> LKML-Reference: <1301041668.14111.52.camel@minggr.sh.intel.com> Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/util/probe-finder.c72
-rw-r--r--tools/perf/util/probe-finder.h2
2 files changed, 74 insertions, 0 deletions
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 194f9e2a3285..ff416b85f7e8 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1435,6 +1435,38 @@ static int find_probe_point_by_func(struct probe_finder *pf)
return _param.retval;
}
+struct pubname_callback_param {
+ char *function;
+ char *file;
+ Dwarf_Die *cu_die;
+ Dwarf_Die *sp_die;
+ int found;
+};
+
+static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
+{
+ struct pubname_callback_param *param = data;
+
+ if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
+ if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
+ return DWARF_CB_OK;
+
+ if (die_compare_name(param->sp_die, param->function)) {
+ if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
+ return DWARF_CB_OK;
+
+ if (param->file &&
+ strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
+ return DWARF_CB_OK;
+
+ param->found = 1;
+ return DWARF_CB_ABORT;
+ }
+ }
+
+ return DWARF_CB_OK;
+}
+
/* Find probe points from debuginfo */
static int find_probes(int fd, struct probe_finder *pf)
{
@@ -1461,6 +1493,27 @@ static int find_probes(int fd, struct probe_finder *pf)
off = 0;
line_list__init(&pf->lcache);
+
+ /* Fastpath: lookup by function name from .debug_pubnames section */
+ if (pp->function) {
+ struct pubname_callback_param pubname_param = {
+ .function = pp->function,
+ .file = pp->file,
+ .cu_die = &pf->cu_die,
+ .sp_die = &pf->sp_die,
+ };
+ struct dwarf_callback_param probe_param = {
+ .data = pf,
+ };
+
+ dwarf_getpubnames(dbg, pubname_search_cb, &pubname_param, 0);
+ if (pubname_param.found) {
+ ret = probe_point_search_cb(&pf->sp_die, &probe_param);
+ if (ret)
+ goto found;
+ }
+ }
+
/* Loop on CUs (Compilation Unit) */
while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
/* Get the DIE(Debugging Information Entry) of this CU */
@@ -1488,6 +1541,8 @@ static int find_probes(int fd, struct probe_finder *pf)
}
off = noff;
}
+
+found:
line_list__free(&pf->lcache);
if (dwfl)
dwfl_end(dwfl);
@@ -1895,6 +1950,22 @@ int find_line_range(int fd, struct line_range *lr)
return -EBADF;
}
+ /* Fastpath: lookup by function name from .debug_pubnames section */
+ if (lr->function) {
+ struct pubname_callback_param pubname_param = {
+ .function = lr->function, .file = lr->file,
+ .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
+ struct dwarf_callback_param line_range_param = {
+ .data = (void *)&lf, .retval = 0};
+
+ dwarf_getpubnames(dbg, pubname_search_cb, &pubname_param, 0);
+ if (pubname_param.found) {
+ line_range_search_cb(&lf.sp_die, &line_range_param);
+ if (lf.found)
+ goto found;
+ }
+ }
+
/* Loop on CUs (Compilation Unit) */
while (!lf.found && ret >= 0) {
if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
@@ -1923,6 +1994,7 @@ int find_line_range(int fd, struct line_range *lr)
off = noff;
}
+found:
/* Store comp_dir */
if (lf.found) {
comp_dir = cu_get_comp_dir(&lf.cu_die);
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index beaefc3c1223..605730a366db 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -49,6 +49,7 @@ struct probe_finder {
Dwarf_Addr addr; /* Address */
const char *fname; /* Real file name */
Dwarf_Die cu_die; /* Current CU */
+ Dwarf_Die sp_die;
struct list_head lcache; /* Line cache for lazy match */
/* For variable searching */
@@ -83,6 +84,7 @@ struct line_finder {
int lno_s; /* Start line number */
int lno_e; /* End line number */
Dwarf_Die cu_die; /* Current CU */
+ Dwarf_Die sp_die;
int found;
};