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[PATCH 13/18] perf tools: Stop copying kallsyms into the perf.data file header

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From: Arnaldo Carvalho de Melo <acme@redhat.com>

Since we now ask libtraceevent, the only user of this payload, to use
perf's symbol resolution routines, there is no need to carry about
~4.5MB per perf.data when we can get it from one of the places the perf
symbol resolution looks for that symtab (debuginfo, ~/.debug/,
/proc/kallsyms, --symfs, etc), using the kernel and modules build-ids to
make sure the right table is used.

Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/n/tip-h89ituf9rso2rv1v7kjrbeda@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/trace-event-info.c | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/tools/perf/util/trace-event-info.c b/tools/perf/util/trace-event-info.c
index eb72716017ac..22245986e59e 100644
--- a/tools/perf/util/trace-event-info.c
+++ b/tools/perf/util/trace-event-info.c
@@ -341,20 +341,14 @@ out:
 
 static int record_proc_kallsyms(void)
 {
-	unsigned int size;
-	const char *path = "/proc/kallsyms";
-	struct stat st;
-	int ret, err = 0;
-
-	ret = stat(path, &st);
-	if (ret < 0) {
-		/* not found */
-		size = 0;
-		if (write(output_fd, &size, 4) != 4)
-			err = -EIO;
-		return err;
-	}
-	return record_file(path, 4);
+	unsigned long long size = 0;
+	/*
+	 * Just to keep older perf.data file parsers happy, record a zero
+	 * sized kallsyms file, i.e. do the same thing that was done when
+	 * /proc/kallsyms (or something specified via --kallsyms, in a
+	 * different path) couldn't be read.
+	 */
+	return write(output_fd, &size, 4) != 4 ? -EIO : 0;
 }
 
 static int record_ftrace_printk(void)
-- 
2.1.0

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Thread

[GIT PULL 00/18] perf/core improvements and fixes Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:00 +0200
  [PATCH 01/18] perf test: Check for refcnt in thread_map test Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:00 +0200
  [PATCH 06/18] perf symbols: Add front end cache for DSO symbol lookup Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 12/18] perf tools: Stop reading the kallsyms data from perf.data Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 11/18] perf script: Switch from perf.data's kallsyms to perf's symbol resolver Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
    Re: [PATCH 11/18] perf script: Switch from perf.data's kallsyms to  perf's symbol resolver Jiri Olsa <jolsa@redhat.com> - 2015-08-03 19:50 +0200
      Re: [PATCH 11/18] perf script: Switch from perf.data's kallsyms to  perf's symbol resolver Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-08-03 21:10 +0200
        Re: [PATCH 11/18] perf script: Switch from perf.data's kallsyms to  perf's symbol resolver Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-08-03 21:30 +0200
          Re: [PATCH 11/18] perf script: Switch from perf.data's kallsyms to  perf's symbol resolver Jiri Olsa <jolsa@redhat.com> - 2015-08-03 22:20 +0200
  [PATCH 03/18] perf evlist: Use bool instead of target argument in propagate_maps() Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 18/18] perf script: Add option --show-switch-events Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 16/18] perf record: Add option --switch-events to select PERF_RECORD_SWITCH events Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 07/18] perf symbols: Introduce map__is_(kernel,kmodule)() Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 08/18] tools lib traceevent: Allow setting an alternative symbol resolver Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 13/18] perf tools: Stop copying kallsyms into the perf.data file header Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 15/18] perf tools: Add new PERF_RECORD_SWITCH event Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 17/18] perf script: Don't assume evsel position of tracking events Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 09/18] perf symbols: Provide libtraceevent callback to resolve kernel symbols Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 14/18] perf: Add PERF_RECORD_SWITCH to indicate context switches Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200
  [PATCH 05/18] perf header: Use argv style storage for cmdline feature data Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-07-24 04:10 +0200

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