Re: [PATCH] perf report: Add option to collapse undesired parts ofcall graph

[Greg Price]

On Fri, Jan 11, 2013 at 02:27:36AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Fri, Dec 07, 2012 at 02:30:44AM -0500, Greg Price escreveu:
> > If an application has an expensive function implemented with a large
> > tree of calls to helper functions, the default call-graph presentation
> > will be dominated by the many different call-chains within that
> > function.  By treating the function as a black box, we can collect the
> > call-chains leading into the function and compactly identify what to
> > blame for expensive calls.
> 
> Looks like an interesting feature, will review this soon,

Hi Arnaldo,

Have you had a chance to look at this yet?

Cheers,
Greg





> > For example, in this report the callers of garbage_collect() are
> > scattered across the tree:
> > $ perf report -d ruby 2>- | grep -m10 ^[^#]*[a-z]
> >     22.03%     ruby  [.] gc_mark
> >                --- gc_mark
> >                   |--59.40%-- mark_keyvalue
> >                   |          st_foreach
> >                   |          gc_mark_children
> >                   |          |--99.75%-- rb_gc_mark
> >                   |          |          rb_vm_mark
> >                   |          |          gc_mark_children
> >                   |          |          gc_marks
> >                   |          |          |--99.00%-- garbage_collect
> > 
> > If we make garbage_collect() a black box, its callers are coalesced:
> > $ perf report --blackbox garbage_collect -d ruby 2>- | grep -m10 ^[^#]*[a-z]
> >     72.92%     ruby  [.] garbage_collect
> >                --- garbage_collect
> >                    vm_xmalloc
> >                   |--47.08%-- ruby_xmalloc
> >                   |          st_insert2
> >                   |          rb_hash_aset
> >                   |          |--98.45%-- features_index_add
> >                   |          |          rb_provide_feature
> >                   |          |          rb_require_safe
> >                   |          |          vm_call_method
> > 
> > Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> > Cc: Paul Mackerras <paulus@xxxxxxxxx>
> > Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> > Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxxxxxxx>
> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Cc: David Ahern <dsahern@xxxxxxxxx>
> > Signed-off-by: Greg Price <price@xxxxxxx>
> > ---
> >  tools/perf/builtin-report.c | 17 +++++++++++++++--
> >  tools/perf/builtin-top.c    |  3 +--
> >  tools/perf/util/map.h       |  4 +++-
> >  tools/perf/util/session.c   | 29 ++++++++++++++++++-----------
> >  tools/perf/util/session.h   |  5 +++++
> >  5 files changed, 42 insertions(+), 16 deletions(-)
> > 
> > diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> > index a61725d..3bbda35 100644
> > --- a/tools/perf/builtin-report.c
> > +++ b/tools/perf/builtin-report.c
> > @@ -70,7 +70,7 @@ 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);
> > +						 sample, &parent, al);
> >  		if (err)
> >  			return err;
> >  	}
> > @@ -141,7 +141,7 @@ static int perf_evsel__add_hist_entry(struct perf_evsel *evsel,
> >  
> >  	if ((sort__has_parent || symbol_conf.use_callchain) && sample->callchain) {
> >  		err = machine__resolve_callchain(machine, evsel, al->thread,
> > -						 sample, &parent);
> > +						 sample, &parent, al);
> >  		if (err)
> >  			return err;
> >  	}
> > @@ -607,6 +607,8 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
> >  		     "Default: fractal,0.5,callee", &parse_callchain_opt, callchain_default_opt),
> >  	OPT_BOOLEAN('G', "inverted", &report.inverted_callchain,
> >  		    "alias for inverted call graph"),
> > +	OPT_STRING(0, "blackbox", &blackbox_pattern, "regex",
> > +		   "functions to treat as black boxes in call graphs, collapsing callees"),
> >  	OPT_STRING('d', "dsos", &symbol_conf.dso_list_str, "dso[,dso...]",
> >  		   "only consider symbols in these dsos"),
> >  	OPT_STRING('c', "comms", &symbol_conf.comm_list_str, "comm[,comm...]",
> > @@ -687,6 +689,17 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
> >  
> >  	}
> >  
> > +	if (blackbox_pattern) {
> > +		int err = regcomp(&blackbox_regex, blackbox_pattern, REG_EXTENDED);
> > +		if (err) {
> > +			char buf[BUFSIZ];
> > +			regerror(err, &blackbox_regex, buf, sizeof(buf));
> > +			pr_err("Invalid blackbox regex: %s\n%s", blackbox_pattern, buf);
> > +			goto error;
> > +		}
> > +		have_blackbox = 1;
> > +	}
> > +
> >  	if (strcmp(report.input_name, "-") != 0)
> >  		setup_browser(true);
> >  	else {
> > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> > index ff6db80..ee969b5 100644
> > --- a/tools/perf/builtin-top.c
> > +++ b/tools/perf/builtin-top.c
> > @@ -786,8 +786,7 @@ static void perf_event__process_sample(struct perf_tool *tool,
> >  		    sample->callchain) {
> >  			err = machine__resolve_callchain(machine, evsel,
> >  							 al.thread, sample,
> > -							 &parent);
> > -
> > +							 &parent, NULL);
> >  			if (err)
> >  				return;
> >  		}
> > diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
> > index d2250fc..6d1b8e1 100644
> > --- a/tools/perf/util/map.h
> > +++ b/tools/perf/util/map.h
> > @@ -23,6 +23,7 @@ struct ref_reloc_sym;
> >  struct map_groups;
> >  struct machine;
> >  struct perf_evsel;
> > +struct addr_location;
> >  
> >  struct map {
> >  	union {
> > @@ -163,7 +164,8 @@ int machine__resolve_callchain(struct machine *machine,
> >  			       struct perf_evsel *evsel,
> >  			       struct thread *thread,
> >  			       struct perf_sample *sample,
> > -			       struct symbol **parent);
> > +			       struct symbol **parent,
> > +			       struct addr_location *root_al);
> >  int maps__set_kallsyms_ref_reloc_sym(struct map **maps, const char *symbol_name,
> >  				     u64 addr);
> >  
> > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> > index 8cdd232..9a8798c 100644
> > --- a/tools/perf/util/session.c
> > +++ b/tools/perf/util/session.c
> > @@ -19,6 +19,10 @@
> >  #include "unwind.h"
> >  #include "vdso.h"
> >  
> > +regex_t blackbox_regex;
> > +const char *blackbox_pattern;
> > +int have_blackbox = 0;
> > +
> >  static int perf_session__open(struct perf_session *self, bool force)
> >  {
> >  	struct stat input_stat;
> > @@ -226,11 +230,10 @@ void machine__remove_thread(struct machine *self, struct thread *th)
> >  	list_add_tail(&th->node, &self->dead_threads);
> >  }
> >  
> > -static bool symbol__match_parent_regex(struct symbol *sym)
> > +static bool symbol__match_regex(struct symbol *sym, regex_t *regex)
> >  {
> > -	if (sym->name && !regexec(&parent_regex, sym->name, 0, NULL, 0))
> > +	if (sym->name && !regexec(regex, sym->name, 0, NULL, 0))
> >  		return 1;
> > -
> >  	return 0;
> >  }
> >  
> > @@ -295,8 +298,8 @@ struct branch_info *machine__resolve_bstack(struct machine *self,
> >  static int machine__resolve_callchain_sample(struct machine *machine,
> >  					     struct thread *thread,
> >  					     struct ip_callchain *chain,
> > -					     struct symbol **parent)
> > -
> > +					     struct symbol **parent,
> > +					     struct addr_location *root_al)
> >  {
> >  	u8 cpumode = PERF_RECORD_MISC_USER;
> >  	unsigned int i;
> > @@ -347,8 +350,13 @@ static int machine__resolve_callchain_sample(struct machine *machine,
> >  					   MAP__FUNCTION, ip, &al, NULL);
> >  		if (al.sym != NULL) {
> >  			if (sort__has_parent && !*parent &&
> > -			    symbol__match_parent_regex(al.sym))
> > +			    symbol__match_regex(al.sym, &parent_regex))
> >  				*parent = al.sym;
> > +			else if (have_blackbox && root_al &&
> > +			         symbol__match_regex(al.sym, &blackbox_regex)) {
> > +				*root_al = al;
> > +				callchain_cursor_reset(&callchain_cursor);
> > +			}
> >  			if (!symbol_conf.use_callchain)
> >  				break;
> >  		}
> > @@ -373,15 +381,15 @@ int machine__resolve_callchain(struct machine *machine,
> >  			       struct perf_evsel *evsel,
> >  			       struct thread *thread,
> >  			       struct perf_sample *sample,
> > -			       struct symbol **parent)
> > -
> > +			       struct symbol **parent,
> > +			       struct addr_location *root_al)
> >  {
> >  	int ret;
> >  
> >  	callchain_cursor_reset(&callchain_cursor);
> >  
> >  	ret = machine__resolve_callchain_sample(machine, thread,
> > -						sample->callchain, parent);
> > +	                                        sample->callchain, parent, root_al);
> >  	if (ret)
> >  		return ret;
> >  
> > @@ -1603,9 +1611,8 @@ 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) != 0) {
> > +					       sample, NULL, NULL) != 0) {
> >  			if (verbose)
> >  				error("Failed to resolve callchain. Skipping\n");
> >  			return;
> > diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
> > index 0eae00a..6db3e55 100644
> > --- a/tools/perf/util/session.h
> > +++ b/tools/perf/util/session.h
> > @@ -1,6 +1,7 @@
> >  #ifndef __PERF_SESSION_H
> >  #define __PERF_SESSION_H
> >  
> > +#include <regex.h>
> >  #include "hist.h"
> >  #include "event.h"
> >  #include "header.h"
> > @@ -9,6 +10,10 @@
> >  #include <linux/rbtree.h>
> >  #include <linux/perf_event.h>
> >  
> > +extern regex_t blackbox_regex;
> > +extern const char *blackbox_pattern;
> > +extern int have_blackbox;
> > +
> >  struct sample_queue;
> >  struct ip_callchain;
> >  struct thread;
> > -- 
> > 1.7.11.3
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