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authorWaiman Long <Waiman.Long@hp.com>2013-10-18 10:38:49 -0400
committerArnaldo Carvalho de Melo <acme@redhat.com>2013-10-21 17:36:25 -0300
commit5dbb6e81d85e55ee2b4cf523c1738e16f63e5400 (patch)
tree334d7cd3884dde1e7f9d35e0be561f82edc92ccf /tools/perf
parent91e95617429cb272fd908b1928a1915b37b9655f (diff)
downloadop-kernel-dev-5dbb6e81d85e55ee2b4cf523c1738e16f63e5400.zip
op-kernel-dev-5dbb6e81d85e55ee2b4cf523c1738e16f63e5400.tar.gz
perf top: Add --max-stack option to limit callchain stack scan
When the callgraph function is enabled (-G), it may take a long time to scan all the stack data and merge them accordingly. This patch adds a new --max-stack option to perf-top to limit the depth of callchain stack data to look at to reduce the time it takes for perf-top to finish its processing. It reduces the amount of information provided to the user in exchange for faster speed. Signed-off-by: Waiman Long <Waiman.Long@hp.com> Acked-by: David Ahern <dsahern@gmail.com> Tested-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: David Ahern <dsahern@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Scott J Norton <scott.norton@hp.com> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1382107129-2010-5-git-send-email-Waiman.Long@hp.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/Documentation/perf-top.txt8
-rw-r--r--tools/perf/builtin-top.c8
-rw-r--r--tools/perf/util/top.h1
3 files changed, 15 insertions, 2 deletions
diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt
index f65777c..c16a09e 100644
--- a/tools/perf/Documentation/perf-top.txt
+++ b/tools/perf/Documentation/perf-top.txt
@@ -158,6 +158,14 @@ Default is to monitor all CPUS.
Default: fractal,0.5,callee.
+--max-stack::
+ Set the stack depth limit when parsing the callchain, anything
+ beyond the specified depth will be ignored. This is a trade-off
+ between information loss and faster processing especially for
+ workloads that can have a very long callchain stack.
+
+ Default: 127
+
--ignore-callees=<regex>::
Ignore callees of the function(s) matching the given regex.
This has the effect of collecting the callers of each such
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 112cb7d..386d833 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -771,7 +771,7 @@ static void perf_event__process_sample(struct perf_tool *tool,
err = machine__resolve_callchain(machine, evsel,
al.thread, sample,
&parent, &al,
- PERF_MAX_STACK_DEPTH);
+ top->max_stack);
if (err)
return;
}
@@ -1048,10 +1048,11 @@ int cmd_top(int argc, const char **argv, const char *prefix __maybe_unused)
.user_freq = UINT_MAX,
.user_interval = ULLONG_MAX,
.freq = 4000, /* 4 KHz */
- .target = {
+ .target = {
.uses_mmap = true,
},
},
+ .max_stack = PERF_MAX_STACK_DEPTH,
.sym_pcnt_filter = 5,
};
struct perf_record_opts *opts = &top.record_opts;
@@ -1110,6 +1111,9 @@ int cmd_top(int argc, const char **argv, const char *prefix __maybe_unused)
OPT_CALLBACK_DEFAULT('G', "call-graph", &top.record_opts,
"mode[,dump_size]", record_callchain_help,
&parse_callchain_opt, "fp"),
+ OPT_INTEGER(0, "max-stack", &top.max_stack,
+ "Set the maximum stack depth when parsing the callchain. "
+ "Default: " __stringify(PERF_MAX_STACK_DEPTH)),
OPT_CALLBACK(0, "ignore-callees", NULL, "regex",
"ignore callees of these functions in call graphs",
report_parse_ignore_callees_opt),
diff --git a/tools/perf/util/top.h b/tools/perf/util/top.h
index b554ffc..88cfeaf 100644
--- a/tools/perf/util/top.h
+++ b/tools/perf/util/top.h
@@ -24,6 +24,7 @@ struct perf_top {
u64 exact_samples;
u64 guest_us_samples, guest_kernel_samples;
int print_entries, count_filter, delay_secs;
+ int max_stack;
bool hide_kernel_symbols, hide_user_symbols, zero;
bool use_tui, use_stdio;
bool kptr_restrict_warned;
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