From 91e95617429cb272fd908b1928a1915b37b9655f Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Fri, 18 Oct 2013 10:38:48 -0400 Subject: [PATCH] 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/Documentation/perf-report.txt | 8 ++++++++ tools/perf/builtin-report.c | 22 +++++++++++++++++----- tools/perf/builtin-top.c | 3 ++- tools/perf/util/machine.c | 14 +++++++++----- tools/perf/util/machine.h | 3 ++- tools/perf/util/session.c | 3 ++- 6 files changed, 40 insertions(+), 13 deletions(-) diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt index be5ad87b6c3d..10a279871251 100644 --- a/tools/perf/Documentation/perf-report.txt +++ b/tools/perf/Documentation/perf-report.txt @@ -141,6 +141,14 @@ OPTIONS Default: fractal,0.5,callee,function. +--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 + -G:: --inverted:: alias for inverted caller based call graph. 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", diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index d934f707ee74..112cb7d68e64 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -770,7 +770,8 @@ static void perf_event__process_sample(struct perf_tool *tool, sample->callchain) { err = machine__resolve_callchain(machine, evsel, al.thread, sample, - &parent, &al); + &parent, &al, + PERF_MAX_STACK_DEPTH); if (err) return; } diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 6b861aefd99a..ea93425cce95 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -1253,10 +1253,12 @@ static int machine__resolve_callchain_sample(struct machine *machine, struct thread *thread, struct ip_callchain *chain, struct symbol **parent, - struct addr_location *root_al) + struct addr_location *root_al, + int max_stack) { u8 cpumode = PERF_RECORD_MISC_USER; - unsigned int i; + int chain_nr = min(max_stack, (int)chain->nr); + int i; int err; callchain_cursor_reset(&callchain_cursor); @@ -1266,7 +1268,7 @@ static int machine__resolve_callchain_sample(struct machine *machine, return 0; } - for (i = 0; i < chain->nr; i++) { + for (i = 0; i < chain_nr; i++) { u64 ip; struct addr_location al; @@ -1338,12 +1340,14 @@ int machine__resolve_callchain(struct machine *machine, struct thread *thread, struct perf_sample *sample, struct symbol **parent, - struct addr_location *root_al) + struct addr_location *root_al, + int max_stack) { int ret; ret = machine__resolve_callchain_sample(machine, thread, - sample->callchain, parent, root_al); + sample->callchain, parent, + root_al, max_stack); if (ret) return ret; diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index d44c09bdc45e..4c1f5d567f54 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -92,7 +92,8 @@ int machine__resolve_callchain(struct machine *machine, struct thread *thread, struct perf_sample *sample, struct symbol **parent, - struct addr_location *root_al); + struct addr_location *root_al, + int max_stack); /* * Default guest kernel is defined by parameter --guestkallsyms diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 19fc71678c8e..854c5aa4db0d 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -1512,7 +1512,8 @@ void perf_evsel__print_ip(struct perf_evsel *evsel, union perf_event *event, if (symbol_conf.use_callchain && sample->callchain) { if (machine__resolve_callchain(machine, evsel, al.thread, - sample, NULL, NULL) != 0) { + sample, NULL, NULL, + PERF_MAX_STACK_DEPTH) != 0) { if (verbose) error("Failed to resolve callchain. Skipping\n"); return; -- 2.30.2