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perf top: Add --max-stack option to limit callchain stack scan

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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>
This commit is contained in:
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. 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=<regex>::
Ignore callees of the function(s) matching the given regex. Ignore callees of the function(s) matching the given regex.
This has the effect of collecting the callers of each such 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, err = machine__resolve_callchain(machine, evsel,
al.thread, sample, al.thread, sample,
&parent, &al, &parent, &al,
PERF_MAX_STACK_DEPTH); top->max_stack);
if (err) if (err)
return; return;
} }
@ -1048,10 +1048,11 @@ int cmd_top(int argc, const char **argv, const char *prefix __maybe_unused)
.user_freq = UINT_MAX, .user_freq = UINT_MAX,
.user_interval = ULLONG_MAX, .user_interval = ULLONG_MAX,
.freq = 4000, /* 4 KHz */ .freq = 4000, /* 4 KHz */
.target = { .target = {
.uses_mmap = true, .uses_mmap = true,
}, },
}, },
.max_stack = PERF_MAX_STACK_DEPTH,
.sym_pcnt_filter = 5, .sym_pcnt_filter = 5,
}; };
struct perf_record_opts *opts = &top.record_opts; 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, OPT_CALLBACK_DEFAULT('G', "call-graph", &top.record_opts,
"mode[,dump_size]", record_callchain_help, "mode[,dump_size]", record_callchain_help,
&parse_callchain_opt, "fp"), &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", OPT_CALLBACK(0, "ignore-callees", NULL, "regex",
"ignore callees of these functions in call graphs", "ignore callees of these functions in call graphs",
report_parse_ignore_callees_opt), report_parse_ignore_callees_opt),

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

@ -24,6 +24,7 @@ struct perf_top {
u64 exact_samples; u64 exact_samples;
u64 guest_us_samples, guest_kernel_samples; u64 guest_us_samples, guest_kernel_samples;
int print_entries, count_filter, delay_secs; int print_entries, count_filter, delay_secs;
int max_stack;
bool hide_kernel_symbols, hide_user_symbols, zero; bool hide_kernel_symbols, hide_user_symbols, zero;
bool use_tui, use_stdio; bool use_tui, use_stdio;
bool kptr_restrict_warned; bool kptr_restrict_warned;