[RFC PATCH v7 36/37] perf tools: Suppress probing messages when probing by BPF loading

Wang Nan
2015-06-12T05:37:28Z

This patch suppress message output by add_perf_probe_events() and
del_perf_probe_events() if they are triggered by BPF loading. Before
this patch, when using 'perf record' with BPF object/source as event
selector, following message will be output:

Added new event:
perf_bpf_probe:lock_page_ret (on __lock_page%return)
You can now use it in all perf tools, such as:
perf record -e perf_bpf_probe:lock_page_ret -aR sleep 1
...
Removed event: perf_bpf_probe:lock_page_ret

Which is misleading, especially 'use it in all perf tools' because they
will be removed after 'pref record' exit.

In this patch, a 'silent' field is appended into probe_conf to control
output. bpf__{,un}probe() set it to true when calling
{add,del}_perf_probe_events().

Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
tools/perf/util/bpf-loader.c | 6 ++++++
tools/perf/util/probe-event.c | 19 ++++++++++++++-----
tools/perf/util/probe-event.h | 1 +
3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 00fb94f..2936adf 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -197,6 +197,7 @@ static bool is_probing = false;
int bpf__unprobe(void)
{
struct strfilter *delfilter;
+ bool old_silent = probe_conf.silent;
int ret;

if (!is_probing)
@@ -208,7 +209,9 @@ int bpf__unprobe(void)
return -ENOMEM;
}

+ probe_conf.silent = true;
ret = del_perf_probe_events(delfilter);
+ probe_conf.silent = old_silent;
strfilter__delete(delfilter);
if (ret < 0 && is_probing)
pr_err("Error: failed to delete events: %s\n",
@@ -221,15 +224,18 @@ int bpf__unprobe(void)
int bpf__probe(void)
{
int err;
+ bool old_silent = probe_conf.silent;

if (nr_probe_events <= 0)
return 0;

+ probe_conf.silent = true;
probe_conf.max_probes = MAX_PROBES;
/* Let add_perf_probe_events keeps probe_trace_event */
err = add_perf_probe_events(probe_event_array,
nr_probe_events,
false);
+ probe_conf.silent = old_silent;

/* add_perf_probe_events return negative when fail */
if (err < 0)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 1609a5e..a46bef3 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -51,7 +51,9 @@
#define PERFPROBE_GROUP "probe"

bool probe_event_dry_run; /* Dry run flag */
-struct probe_conf probe_conf;
+struct probe_conf probe_conf = {
+ .silent = false,
+};

#define semantic_error(msg ...) pr_err("Semantic error :" msg)

@@ -2416,7 +2418,10 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,

safename = (pev->point.function && !strisglob(pev->point.function));
ret = 0;
- pr_info("Added new event%s\n", (ntevs > 1) ? "s:" : ":");
+ if (!probe_conf.silent)
+ pr_info("Added new event%s\n", (ntevs > 1) ? "s:" : ":");
+ else
+ pr_debug("Added new event%s\n", (ntevs > 1) ? "s:" : ":");
for (i = 0; i < ntevs; i++) {
tev = &tevs[i];
/* Skip if the symbol is out of .text (marked previously) */
@@ -2466,7 +2471,8 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
group = pev->group;
pev->event = tev->event;
pev->group = tev->group;
- show_perf_probe_event(pev, tev->point.module);
+ if (!probe_conf.silent)
+ show_perf_probe_event(pev, tev->point.module);
/* Trick here - restore current event/group */
pev->event = (char *)event;
pev->group = (char *)group;
@@ -2483,7 +2489,7 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
warn_uprobe_event_compat(tev);

/* Note that it is possible to skip all events because of blacklist */
- if (ret >= 0 && tev->event) {
+ if (ret >= 0 && tev->event && !probe_conf.silent) {
/* Show how to use the event. */
pr_info("\nYou can now use it in all perf tools, such as:\n\n");
pr_info("\tperf record -e %s:%s -aR sleep 1\n\n", tev->group,
@@ -2766,7 +2772,10 @@ static int __del_trace_probe_event(int fd, struct str_node *ent)
goto error;
}

- pr_info("Removed event: %s\n", ent->s);
+ if (!probe_conf.silent)
+ pr_info("Removed event: %s\n", ent->s);
+ else
+ pr_debug("Removed event: %s\n", ent->s);
return 0;
error:
pr_warning("Failed to delete event: %s\n",
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 40dd22b..dd7c630 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -13,6 +13,7 @@ struct probe_conf {
bool force_add;
bool no_inlines;
int max_probes;
+ bool silent;
};
extern struct probe_conf probe_conf;
extern bool probe_event_dry_run;
--
1.8.3.4