lkml.org 
[lkml]   [2022]   [Jun]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 6/7] perf record: Allow to specify max stack depth of fp callchain
Date
Currently it has no interface to specify the max stack depth for perf
record. Extend the command line parameter to accept a number after
'fp' to specify the depth like '--call-graph fp,32'.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/perf/Documentation/perf-record.txt | 5 +++++
tools/perf/util/callchain.c | 18 ++++++++++++------
2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index cf8ad50f3de1..772777c2a52e 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -275,6 +275,11 @@ OPTIONS
User can change the size by passing the size after comma like
"--call-graph dwarf,4096".

+ When "fp" recording is used, perf tries to save stack enties
+ up to the number specified in sysctl.kernel.perf_event_max_stack
+ by default. User can change the number by passing it after comma
+ like "--call-graph fp,32".
+
-q::
--quiet::
Don't print any message, useful for scripting.
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 5c27a4b2e7a7..7e663673f79f 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -31,6 +31,7 @@
#include "callchain.h"
#include "branch.h"
#include "symbol.h"
+#include "util.h"
#include "../perf.h"

#define CALLCHAIN_PARAM_DEFAULT \
@@ -266,12 +267,17 @@ int parse_callchain_record(const char *arg, struct callchain_param *param)
do {
/* Framepointer style */
if (!strncmp(name, "fp", sizeof("fp"))) {
- if (!strtok_r(NULL, ",", &saveptr)) {
- param->record_mode = CALLCHAIN_FP;
- ret = 0;
- } else
- pr_err("callchain: No more arguments "
- "needed for --call-graph fp\n");
+ ret = 0;
+ param->record_mode = CALLCHAIN_FP;
+
+ tok = strtok_r(NULL, ",", &saveptr);
+ if (tok) {
+ unsigned long size;
+
+ size = strtoul(tok, &name, 0);
+ if (size < (unsigned) sysctl__max_stack())
+ param->max_stack = size;
+ }
break;

/* Dwarf style */
--
2.36.1.476.g0c4daa206d-goog
\
 
 \ /
  Last update: 2022-06-15 18:33    [W:0.094 / U:0.812 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site