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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>
hifive-unleashed-5.1
Waiman Long 2013-10-18 10:38:49 -04:00 committed by Arnaldo Carvalho de Melo
parent 91e9561742
commit 5dbb6e81d8
3 changed files with 15 additions and 2 deletions
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8
tools/perf/Documentation/perf-top.txt
View File

@ -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

8
tools/perf/builtin-top.c
View File

@ -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),

1
tools/perf/util/top.h
View File

@ -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;