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perf report: Fall-back to function name comparison for -g srcline 

When a callchain entry has no srcline available, we ended up comparing
the instruction pointer. I consider this to be not too useful. Rather, I
think we should group the entries by function name, which this patch
adds. For people who want to split the data on the IP boundary, using
`-g address` is the correct choice.

Before:

~~~~~
   100.00%    38.86%  [.] main
            |
            |--61.14%--main inlining.cpp:14
            |          std::norm<double> complex:664
            |          std::_Norm_helper<true>::_S_do_it<double> complex:654
            |          std::abs<double> complex:597
            |          std::__complex_abs complex:589
            |          |
            |          |--56.03%--hypot
            |          |          |
            |          |          |--8.45%--__hypot_finite
            |          |          |
            |          |          |--7.62%--__hypot_finite
            |          |          |
            |          |          |--2.29%--__hypot_finite
            |          |          |
            |          |          |--2.24%--__hypot_finite
            |          |          |
            |          |          |--2.06%--__hypot_finite
            |          |          |
            |          |          |--1.81%--__hypot_finite
...
~~~~~

After:

~~~~~
   100.00%    38.86%  [.] main
            |
            |--61.14%--main inlining.cpp:14
            |          std::norm<double> complex:664
            |          std::_Norm_helper<true>::_S_do_it<double> complex:654
            |          std::abs<double> complex:597
            |          std::__complex_abs complex:589
            |          |
            |          |--60.29%--hypot
            |          |          |
            |          |           --56.03%--__hypot_finite
            |          |
            |           --0.85%--cabs
~~~~~

Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yao Jin <yao.jin@linux.intel.com>
Link: http://lkml.kernel.org/r/20171009203310.17362-7-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Milian Wolff 2017-10-09 22:33:00 +02:00 committed by Arnaldo Carvalho de Melo
parent 11ea2515f3
commit cbe50f6172
1 changed files with 12 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
tools/perf/util/callchain.c
View File

@ -645,11 +645,9 @@ enum match_result {
MATCH_GT,
};
static enum match_result match_chain_srcline(struct callchain_cursor_node *node,
struct callchain_list *cnode)
static enum match_result match_chain_strings(const char *left,
const char *right)
{
const char *left = cnode->srcline;
const char *right = node->srcline;
enum match_result ret = MATCH_EQ;
int cmp;
@ -659,10 +657,8 @@ static enum match_result match_chain_srcline(struct callchain_cursor_node *node,
cmp = 1;
else if (left && !right)
cmp = -1;
else if (cnode->ip == node->ip)
cmp = 0;
else
cmp = (cnode->ip < node->ip) ? -1 : 1;
return MATCH_ERROR;
if (cmp != 0)
ret = cmp < 0 ? MATCH_LT : MATCH_GT;
@ -679,10 +675,18 @@ static enum match_result match_chain(struct callchain_cursor_node *node,
struct dso *right_dso = NULL;
if (callchain_param.key == CCKEY_SRCLINE) {
enum match_result match = match_chain_srcline(node, cnode);
enum match_result match = match_chain_strings(cnode->srcline,
node->srcline);
/* if no srcline is available, fallback to symbol name */
if (match == MATCH_ERROR && cnode->ms.sym && node->sym)
match = match_chain_strings(cnode->ms.sym->name,
node->sym->name);
if (match != MATCH_ERROR)
return match;
/* otherwise fall-back to IP-based comparison below */
}
if (cnode->ms.sym && sym && callchain_param.key == CCKEY_FUNCTION) {