From 91e95617429cb272fd908b1928a1915b37b9655f Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Fri, 18 Oct 2013 10:38:48 -0400 Subject: perf report: Add --max-stack option to limit callchain stack scan When callgraph data was included in the perf data file, it may take a long time to scan all those data and merge them together especially if the stored callchains are long and the perf data file itself is large, like a Gbyte or so. The callchain stack is currently limited to PERF_MAX_STACK_DEPTH (127). This is a large value. Usually the callgraph data that developers are most interested in are the first few levels, the rests are usually not looked at. This patch adds a new --max-stack option to perf-report to limit the depth of callchain stack data to look at to reduce the time it takes for perf-report to finish its processing. It trades the presence of trailing stack information with faster speed. The following table shows the elapsed time of doing perf-report on a perf.data file of size 985,531,828 bytes. --max_stack Elapsed Time Output data size ----------- ------------ ---------------- not set 88.0s 124,422,651 64 87.5s 116,303,213 32 87.2s 112,023,804 16 86.6s 94,326,380 8 59.9s 33,697,248 4 40.7s 10,116,637 -g none 27.1s 2,555,810 Signed-off-by: Waiman Long Acked-by: David Ahern Cc: Adrian Hunter Cc: Aswin Chandramouleeswaran Cc: David Ahern Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Scott J Norton Cc: Stephane Eranian Link: http://lkml.kernel.org/r/1382107129-2010-4-git-send-email-Waiman.Long@hp.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-report.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) (limited to 'tools/perf/builtin-report.c') diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index fa68a36bc461..81addcabb356 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -49,6 +49,7 @@ struct perf_report { bool show_threads; bool inverted_callchain; bool mem_mode; + int max_stack; struct perf_read_values show_threads_values; const char *pretty_printing_style; const char *cpu_list; @@ -90,7 +91,8 @@ static int perf_report__add_mem_hist_entry(struct perf_tool *tool, if ((sort__has_parent || symbol_conf.use_callchain) && sample->callchain) { err = machine__resolve_callchain(machine, evsel, al->thread, - sample, &parent, al); + sample, &parent, al, + rep->max_stack); if (err) return err; } @@ -181,7 +183,8 @@ static int perf_report__add_branch_hist_entry(struct perf_tool *tool, if ((sort__has_parent || symbol_conf.use_callchain) && sample->callchain) { err = machine__resolve_callchain(machine, evsel, al->thread, - sample, &parent, al); + sample, &parent, al, + rep->max_stack); if (err) return err; } @@ -244,18 +247,21 @@ out: return err; } -static int perf_evsel__add_hist_entry(struct perf_evsel *evsel, +static int perf_evsel__add_hist_entry(struct perf_tool *tool, + struct perf_evsel *evsel, struct addr_location *al, struct perf_sample *sample, struct machine *machine) { + struct perf_report *rep = container_of(tool, struct perf_report, tool); struct symbol *parent = NULL; int err = 0; struct hist_entry *he; if ((sort__has_parent || symbol_conf.use_callchain) && sample->callchain) { err = machine__resolve_callchain(machine, evsel, al->thread, - sample, &parent, al); + sample, &parent, al, + rep->max_stack); if (err) return err; } @@ -332,7 +338,8 @@ static int process_sample_event(struct perf_tool *tool, if (al.map != NULL) al.map->dso->hit = 1; - ret = perf_evsel__add_hist_entry(evsel, &al, sample, machine); + ret = perf_evsel__add_hist_entry(tool, evsel, &al, sample, + machine); if (ret < 0) pr_debug("problem incrementing symbol period, skipping event\n"); } @@ -772,6 +779,7 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused) .ordered_samples = true, .ordering_requires_timestamps = true, }, + .max_stack = PERF_MAX_STACK_DEPTH, .pretty_printing_style = "normal", }; const struct option options[] = { @@ -812,6 +820,10 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused) OPT_CALLBACK_DEFAULT('g', "call-graph", &report, "output_type,min_percent[,print_limit],call_order", "Display callchains using output_type (graph, flat, fractal, or none) , min percent threshold, optional print limit, callchain order, key (function or address). " "Default: fractal,0.5,callee,function", &parse_callchain_opt, callchain_default_opt), + OPT_INTEGER(0, "max-stack", &report.max_stack, + "Set the maximum stack depth when parsing the callchain, " + "anything beyond the specified depth will be ignored. " + "Default: " __stringify(PERF_MAX_STACK_DEPTH)), OPT_BOOLEAN('G', "inverted", &report.inverted_callchain, "alias for inverted call graph"), OPT_CALLBACK(0, "ignore-callees", NULL, "regex", -- cgit v1.2.3