Commit b38775cf authored Oct 19, 2017 by Milian Wolff Committed by Arnaldo Carvalho de Melo Oct 25, 2017

perf report: Cache failed lookups of inlined frames



When no inlined frames could be found for a given address, we did not
store this information anywhere. That means we potentially do the costly
inliner lookup repeatedly for cases where we know it can never succeed.

This patch makes dso__parse_addr_inlines always return a valid
inline_node. It will be empty when no inliners are found. This enables
us to cache the empty list in the DSO, thereby improving the performance
when many addresses fail to find the inliners.

For my trivial example, the performance impact is already quite
significant:

Before:

~~~~~
 Performance counter stats for 'perf report --stdio --inline -g srcline -s srcline' (5 runs):

        594.804032      task-clock (msec)         #    0.998 CPUs utilized            ( +-  0.07% )
                53      context-switches          #    0.089 K/sec                    ( +-  4.09% )
                 0      cpu-migrations            #    0.000 K/sec                    ( +-100.00% )
             5,687      page-faults               #    0.010 M/sec                    ( +-  0.02% )
     2,300,918,213      cycles                    #    3.868 GHz                      ( +-  0.09% )
     4,395,839,080      instructions              #    1.91  insn per cycle           ( +-  0.00% )
       939,177,205      branches                  # 1578.969 M/sec                    ( +-  0.00% )
        11,824,633      branch-misses             #    1.26% of all branches          ( +-  0.10% )

       0.596246531 seconds time elapsed                                          ( +-  0.07% )
~~~~~

After:

~~~~~
 Performance counter stats for 'perf report --stdio --inline -g srcline -s srcline' (5 runs):

        113.111405      task-clock (msec)         #    0.990 CPUs utilized            ( +-  0.89% )
                29      context-switches          #    0.255 K/sec                    ( +- 54.25% )
                 0      cpu-migrations            #    0.000 K/sec
             5,380      page-faults               #    0.048 M/sec                    ( +-  0.01% )
       432,378,779      cycles                    #    3.823 GHz                      ( +-  0.75% )
       670,057,633      instructions              #    1.55  insn per cycle           ( +-  0.01% )
       141,001,247      branches                  # 1246.570 M/sec                    ( +-  0.01% )
         2,346,845      branch-misses             #    1.66% of all branches          ( +-  0.19% )

       0.114222393 seconds time elapsed                                          ( +-  1.19% )
~~~~~

Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171019113836.5548-3-milian.wolff@kdab.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent bf36eb5c

tools/perf/util/machine.c

+7 −8

Original line number	Diff line number	Diff line
		@@ -2115,9 +2115,10 @@ static int append_inlines(struct callchain_cursor *cursor,
		struct inline_node *inline_node;
		struct inline_list *ilist;
		u64 addr;
		int ret = 1;

		if (!symbol_conf.inline_name \|\| !map \|\| !sym)
		return 1;
		return ret;

		addr = map__rip_2objdump(map, ip);

		@@ -2125,22 +2126,20 @@ static int append_inlines(struct callchain_cursor *cursor,
		if (!inline_node) {
		inline_node = dso__parse_addr_inlines(map->dso, addr, sym);
		if (!inline_node)
		return 1;

		return ret;
		inlines__tree_insert(&map->dso->inlined_nodes, inline_node);
		}

		list_for_each_entry(ilist, &inline_node->val, list) {
		int ret = callchain_cursor_append(cursor, ip, map,
		ret = callchain_cursor_append(cursor, ip, map,
		ilist->symbol, false,
		NULL, 0, 0, 0,
		ilist->srcline);
		NULL, 0, 0, 0, ilist->srcline);

		if (ret != 0)
		return ret;
		}

		return 0;
		return ret;
		}

		static int unwind_entry(struct unwind_entry entry, void arg)

tools/perf/util/srcline.c

+1 −15

Original line number	Diff line number	Diff line
		@@ -353,17 +353,8 @@ static struct inline_node addr2inlines(const char dso_name, u64 addr,
		INIT_LIST_HEAD(&node->val);
		node->addr = addr;

		if (!addr2line(dso_name, addr, NULL, NULL, dso, TRUE, node, sym))
		goto out_free_inline_node;

		if (list_empty(&node->val))
		goto out_free_inline_node;

		addr2line(dso_name, addr, NULL, NULL, dso, true, node, sym);
		return node;

		out_free_inline_node:
		inline_node__delete(node);
		return NULL;
		}

		#else /* HAVE_LIBBFD_SUPPORT */
		@@ -480,11 +471,6 @@ static struct inline_node addr2inlines(const char dso_name, u64 addr,
		out:
		pclose(fp);

		if (list_empty(&node->val)) {
		inline_node__delete(node);
		return NULL;
		}

		return node;
		}

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