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perf report: Fix a wrong offset issue when using /proc/kcore

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When a valid vmlinux is not found, 'perf report' falls back to look at
/proc/kcore. In this case, it will report the impossible large offset.

For example:

  # perf record -b -e cycles:k find /etc/ > /dev/null
  # perf report --stdio --branch-history

    22.77%  _vm_normal_page+18446603336221188162
            |
            ---page_remove_rmap +18446603336221188324
               page_remove_rmap +18446603336221188487 (cycles:5)
               unlock_page_memcg +18446603336221188096
               page_remove_rmap +18446603336221188327 (cycles:1)

The issue is the value which is passed to parameter 'addr' in
__get_srcline() is the objdump address. It's not correct if we calculate
the offset by using 'addr - sym->start'.

This patch creates a new parameter 'ip' in __get_srcline(). It is not
converted to objdump address.

With this patch, the perf report output is:

    22.77%  _vm_normal_page+66
            |
            ---page_remove_rmap +228
               page_remove_rmap +391 (cycles:5)
               unlock_page_memcg +0
               page_remove_rmap +231 (cycles:1)
               page_remove_rmap +236

Committer testing:

Make sure you get any valid vmlinux out of the way, using '-v' on the
'perf report' case and deleting it from places where perf searches them,
like your kernel build dir and the build-id cache, in ~/.debug/.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1514564812-17344-1-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jin Yao
2017-12-30 00:26:52 +08:00
committed by Arnaldo Carvalho de Melo
parent 44df1afdb1
commit 935f5a9d45
6 changed files with 22 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
tools/perf/util/srcline.c
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@@ -496,7 +496,8 @@ out:
#define A2L_FAIL_LIMIT 123
char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
bool show_sym, bool show_addr, bool unwind_inlines)
bool show_sym, bool show_addr, bool unwind_inlines,
u64 ip)
{
char *file = NULL;
unsigned line = 0;
@@ -536,7 +537,7 @@ out:
if (sym) {
if (asprintf(&srcline, "%s+%" PRIu64, show_sym ? sym->name : "",
addr - sym->start) < 0)
ip - sym->start) < 0)
return SRCLINE_UNKNOWN;
} else if (asprintf(&srcline, "%s[%" PRIx64 "]", dso->short_name, addr) < 0)
return SRCLINE_UNKNOWN;
@@ -550,9 +551,9 @@ void free_srcline(char *srcline)
}
char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
bool show_sym, bool show_addr)
bool show_sym, bool show_addr, u64 ip)
{
return __get_srcline(dso, addr, sym, show_sym, show_addr, false);
return __get_srcline(dso, addr, sym, show_sym, show_addr, false, ip);
}
struct srcline_node {