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SubjectRe: [PATCH] perf report: Add option to collapse undesired parts of call graph
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,

- Arnaldo

> 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@chello.nl>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
> Cc: Jiri Olsa <jolsa@redhat.com>
> Cc: David Ahern <dsahern@gmail.com>
> Signed-off-by: Greg Price <price@mit.edu>
> ---
> 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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