linux-kernel - [PATCH] perf report: Fix branch stack mode cannot be set

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Date:	Sun, 15 Feb 2015 10:33:37 +0800
From:	He Kuang <hekuang@...wei.com>
To:	<a.p.zijlstra@...llo.nl>, <paulus@...ba.org>, <mingo@...hat.com>,
	<acme@...nel.org>
CC:	<wangnan0@...wei.com>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] perf report: Fix branch stack mode cannot be set

When perf.data file be abtained by using 'perf record -b', perf report
should use branch stack mode to generate output. But this function is
broken by improper comparison between boolean and constant -1.

before this patch:
$perf report -b -i perf.data
Samples: 16  of event 'cycles', Event count (approx.): 3171896
Overhead  Command  Shared Object      Symbol
  13.59%  ls       [kernel.kallsyms]  [k] prio_tree_remove
  13.16%  ls       [kernel.kallsyms]  [k] change_pte_range
  12.09%  ls       [kernel.kallsyms]  [k] page_fault
  12.02%  ls       [kernel.kallsyms]  [k] zap_pte_range
...

after this patch:
$perf report -b -i perf.data
Samples: 256  of event 'cycles', Event count (approx.): 256
Overhead  Command  Source Shared Object  Source Symbol                               Target Shared Object  Target Symbol
   9.38%  ls       [unknown]             [k] 0000000000000000                        [unknown]             [k] 0000000000000000
   6.25%  ls       libc-2.19.so          [.] _dl_addr                                libc-2.19.so          [.] _dl_addr
   6.25%  ls       [kernel.kallsyms]     [k] zap_pte_range                           [kernel.kallsyms]     [k] zap_pte_range
   6.25%  ls       [kernel.kallsyms]     [k] change_pte_range                        [kernel.kallsyms]     [k] change_pte_range
   0.39%  ls       [kernel.kallsyms]     [k] prio_tree_remove                        [kernel.kallsyms]     [k] prio_tree_remove
...

Signed-off-by: He Kuang <hekuang@...wei.com>
---
 tools/perf/builtin-report.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 2f91094..ecc453b 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -766,7 +766,7 @@ repeat:
 	 * 0/1 means the user chose a mode.
 	 */
 	if (((branch_mode == -1 && has_br_stack) || branch_mode == 1) &&
-	    branch_call_mode == -1) {
+	    !branch_call_mode) {
 		sort__mode = SORT_MODE__BRANCH;
 		symbol_conf.cumulate_callchain = false;
 	}
-- 
2.2.0.33.gc18b867

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