perf probe -F with wildcards

perf probe -F with wildcards

[Arnaldo Carvalho de Melo]

Hi Masami,

	I think this worked at some point?

[root@jouet acme]# perf probe -F | tail
zswap_frontswap_init
zswap_frontswap_invalidate_area
zswap_frontswap_invalidate_page
zswap_frontswap_load
zswap_frontswap_store
zswap_pool_create
zswap_pool_current
zswap_update_total_size
zswap_writeback_entry
zswap_zpool_param_set
[root@jouet acme]# perf probe -F rt_sp*
no symbols found in [kernel.kallsyms], maybe install a debug package?
Failed to load symbols in kernel
[root@jouet acme]# perf probe -F rt_sp\*
no symbols found in [kernel.kallsyms], maybe install a debug package?
Failed to load symbols in kernel
[root@jouet acme]# 


I.e. the second message is misleading :-\

- Arnaldo

Re: perf probe -F with wildcards

[Masami Hiramatsu]

Hi Arnaldo,

On Thu, 14 Jul 2016 21:16:41 -0300
Arnaldo Carvalho de Melo <acme@kernel.org> wrote:

> Hi Masami,
> 
> 	I think this worked at some point?
> 
> [root@jouet acme]# perf probe -F | tail
> zswap_frontswap_init
> zswap_frontswap_invalidate_area
> zswap_frontswap_invalidate_page
> zswap_frontswap_load
> zswap_frontswap_store
> zswap_pool_create
> zswap_pool_current
> zswap_update_total_size
> zswap_writeback_entry
> zswap_zpool_param_set
> [root@jouet acme]# perf probe -F rt_sp*
> no symbols found in [kernel.kallsyms], maybe install a debug package?
> Failed to load symbols in kernel

It seems that 2 problems we have,
- There is no function which starts with rt_sp.
- The error message is not good for that.
If you try perf probe -F acpi_*, you'll see a list of functions.

> [root@jouet acme]# perf probe -F rt_sp\*
> no symbols found in [kernel.kallsyms], maybe install a debug package?
> Failed to load symbols in kernel

So, yeah, it should check symbol loading is really failed and should be
changed as "no symbols match to given filter" etc.

Thank you,

> [root@jouet acme]# 


> 
> 
> I.e. the second message is misleading :-\
> 
> - Arnaldo
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: perf probe -F with wildcards

[Arnaldo Carvalho de Melo]

Em Fri, Jul 15, 2016 at 04:15:48PM +0900, Masami Hiramatsu escreveu:
> On Thu, 14 Jul 2016 21:16:41 -0300
> Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
 
> > 	I think this worked at some point?

> > [root@jouet acme]# perf probe -F | tail
> > zswap_frontswap_init
> > zswap_frontswap_invalidate_area
> > zswap_frontswap_invalidate_page
> > zswap_frontswap_load
> > zswap_frontswap_store
> > zswap_pool_create
> > zswap_pool_current
> > zswap_update_total_size
> > zswap_writeback_entry
> > zswap_zpool_param_set
> > [root@jouet acme]# perf probe -F rt_sp*
> > no symbols found in [kernel.kallsyms], maybe install a debug package?
> > Failed to load symbols in kernel
 
> It seems that 2 problems we have,
> - There is no function which starts with rt_sp.

Yeah, that is the problem at hand, I figured there weren't functions
liek that, but the error message was tottally misleading :-)

> - The error message is not good for that.
> If you try perf probe -F acpi_*, you'll see a list of functions.
> 
> > [root@jouet acme]# perf probe -F rt_sp\*
> > no symbols found in [kernel.kallsyms], maybe install a debug package?
> > Failed to load symbols in kernel
> 
> So, yeah, it should check symbol loading is really failed and should be
> changed as "no symbols match to given filter" etc.

Right,

- Arnaldo

[PATCH] [BUGFIX] perf-probe: Warn unmatched function filter correctly

[Masami Hiramatsu]

Warn unmatched function filter correctly instead of warning
"symbol-loading error", since that can be a filter issue.

>From the technical point of view, this adds a filter chech
in map__load and if there is a filter, it returns -2 (filter-out),
instead of -1 (error), and perf-probe checks it and change
message.

E.g. without this fix:
  ----
  # perf probe -F rt_sp*
  no symbols found in [kernel.kallsyms], maybe install a debug package?
  Failed to load symbols in kernel
  ----
With this fix:
  ----
  # perf probe -F rt_sp*
  no symbols passed the given filter.
  Failed to find symbols matched to "rt_sp*"
    Error: Failed to show functions.
  ----

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 tools/perf/util/map.c         |    3 +++
 tools/perf/util/probe-event.c |   12 ++++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index b39b12a..728129a 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -312,6 +312,9 @@ int map__load(struct map *map, symbol_filter_t filter)
 			pr_warning("%.*s was updated (is prelink enabled?). "
 				"Restart the long running apps that use it!\n",
 				   (int)real_len, name);
+		} else if (filter) {
+			pr_warning("no symbols passed the given filter.\n");
+			return -2;	/* Empty but maybe by the filter */
 		} else {
 			pr_warning("no symbols found in %s, maybe install "
 				   "a debug package?\n", name);
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index d4f8835..953dc1a 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -3312,8 +3312,16 @@ int show_available_funcs(const char *target, struct strfilter *_filter,
 
 	/* Load symbols with given filter */
 	available_func_filter = _filter;
-	if (map__load(map, filter_available_functions)) {
-		pr_err("Failed to load symbols in %s\n", (target) ? : "kernel");
+	ret = map__load(map, filter_available_functions);
+	if (ret) {
+		if (ret == -2) {
+			char *str = strfilter__string(_filter);
+			pr_err("Failed to find symbols matched to \"%s\"\n",
+			       str);
+			free(str);
+		} else
+			pr_err("Failed to load symbols in %s\n",
+			       (target) ? : "kernel");
 		goto end;
 	}
 	if (!dso__sorted_by_name(map->dso, map->type))

[tip:perf/core] perf probe: Warn unmatched function filter correctly

[tip-bot for Masami Hiramatsu]

Commit-ID:  e70493429bb1acaad829caae01c61dd7056fe671
Gitweb:     http://git.kernel.org/tip/e70493429bb1acaad829caae01c61dd7056fe671
Author:     Masami Hiramatsu <mhiramat@kernel.org>
AuthorDate: Tue, 19 Jul 2016 01:12:41 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 18 Jul 2016 19:46:34 -0300

perf probe: Warn unmatched function filter correctly

Warn unmatched function filter correctly instead of warning
"symbol-loading error", since that can be a filter issue.

>From the technical point of view, this adds a filter chech in map__load
and if there is a filter, it returns -2 (filter-out), instead of -1
(error), and perf-probe checks it and change message.

E.g. without this fix:

  # perf probe -F rt_sp*
  no symbols found in [kernel.kallsyms], maybe install a debug package?
  Failed to load symbols in kernel

With this fix:

  # perf probe -F rt_sp*
  no symbols passed the given filter.
  Failed to find symbols matched to "rt_sp*"
    Error: Failed to show functions.

Reported-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/146885835596.16106.2293540792775552481.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/map.c         |  3 +++
 tools/perf/util/probe-event.c | 12 ++++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index b39b12a..728129a 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -312,6 +312,9 @@ int map__load(struct map *map, symbol_filter_t filter)
 			pr_warning("%.*s was updated (is prelink enabled?). "
 				"Restart the long running apps that use it!\n",
 				   (int)real_len, name);
+		} else if (filter) {
+			pr_warning("no symbols passed the given filter.\n");
+			return -2;	/* Empty but maybe by the filter */
 		} else {
 			pr_warning("no symbols found in %s, maybe install "
 				   "a debug package?\n", name);
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index d4f8835..953dc1a 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -3312,8 +3312,16 @@ int show_available_funcs(const char *target, struct strfilter *_filter,
 
 	/* Load symbols with given filter */
 	available_func_filter = _filter;
-	if (map__load(map, filter_available_functions)) {
-		pr_err("Failed to load symbols in %s\n", (target) ? : "kernel");
+	ret = map__load(map, filter_available_functions);
+	if (ret) {
+		if (ret == -2) {
+			char *str = strfilter__string(_filter);
+			pr_err("Failed to find symbols matched to \"%s\"\n",
+			       str);
+			free(str);
+		} else
+			pr_err("Failed to load symbols in %s\n",
+			       (target) ? : "kernel");
 		goto end;
 	}
 	if (!dso__sorted_by_name(map->dso, map->type))