Re: [PATCH 2/2] perf probe: Fix offline module name missmatch issue

2016-04-26 Thread Masami Hiramatsu 
On Tue, 26 Apr 2016 19:55:41 +0530
Ravi Bangoria  wrote:

> Perf can add a probe on kernel module which has not been loaded yet.
> Current implementation finds module name from path. But if filename
> is different from actual module name then perf fails to register
> probe while loading module because of mismatch in names. For example,
> samples/kobject/kobject-example.ko is loaded as kobject_example.
> 
> Before applying patch:
> 
>   $ sudo ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show
> Added new event:
>   probe:foo_show   (on foo_show in kobject-example)
> 
> You can now use it in all perf tools, such as:
> 
> perf record -e probe:foo_show -aR sleep 1
> 
>   $ cat /sys/kernel/debug/tracing/kprobe_events
> p:probe/foo_show kobject-example:foo_show
> 
>   $ insmod kobject-example.ko
> 
>   $ lsmod
> Module  Size  Used by
> kobject_example16384  0
> 
>   Generate read to /sys/kernel/kobject_example/foo while recording data
>   with below command
>   $ sudo ./perf record -e probe:foo_show -a
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.093 MB perf.data ]
> 
>   $./perf report --stdio -F overhead,comm,dso,sym
> Error:
> The perf.data.old file has no samples!
> 
> After applying patch:
> 
>   $ sudo ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show
> Added new event:
>   probe:foo_show   (on foo_show in kobject_example)
> 
> You can now use it in all perf tools, such as:
> 
> perf record -e probe:foo_show -aR sleep 1
> 
>   $ sudo cat /sys/kernel/debug/tracing/kprobe_events
> p:probe/foo_show kobject_example:foo_show
> 
>   $ insmod kobject-example.ko
> 
>   $ lsmod
> Module  Size  Used by
> kobject_example16384  0
> 
>   Generate read to /sys/kernel/kobject_example/foo while recording data
>   with below command
>   $ sudo ./perf record -e probe:foo_show -a
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.097 MB perf.data (8 samples) ]
> 
>   $ sudo ./perf report  --stdio -F overhead,comm,dso,sym
> ...
> # Samples: 8  of event 'probe:foo_show'
> # Event count (approx.): 8
> #
> # Overhead  Command  Shared Object  Symbol
> #   ...  .  
> #
>100.00%  cat  [kobject_example]  [k] foo_show
> 

Looks good to me :)

Acked-by: Masami Hiramatsu 

Thank you!

> Signed-off-by: Ravi Bangoria 
> ---
>  tools/perf/util/probe-event.c | 19 +--
>  1 file changed, 5 insertions(+), 14 deletions(-)
> 
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index d58de20..26803e1 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -642,32 +642,23 @@ static int add_module_to_probe_trace_events(struct 
> probe_trace_event *tevs,
>   int ntevs, const char *module)
>  {
>   int i, ret = 0;
> - char *tmp;
> + char *mod_name = NULL;
>  
>   if (!module)
>   return 0;
>  
> - tmp = strrchr(module, '/');
> - if (tmp) {
> - /* This is a module path -- get the module name */
> - module = strdup(tmp + 1);
> - if (!module)
> - return -ENOMEM;
> - tmp = strchr(module, '.');
> - if (tmp)
> - *tmp = '\0';
> - tmp = (char *)module;   /* For free() */
> - }
> + mod_name = find_module_name(module);
>  
>   for (i = 0; i < ntevs; i++) {
> - tevs[i].point.module = strdup(module);
> + tevs[i].point.module =
> + strdup(mod_name ? mod_name : module);
>   if (!tevs[i].point.module) {
>   ret = -ENOMEM;
>   break;
>   }
>   }
>  
> - free(tmp);
> + free(mod_name);
>   return ret;
>  }
>  
> -- 
> 1.9.1
> 


-- 
Masami Hiramatsu

Re: [PATCH 2/2] perf probe: Fix offline module name missmatch issue

2016-04-26 Thread Masami Hiramatsu 
On Tue, 26 Apr 2016 19:55:41 +0530
Ravi Bangoria  wrote:

> Perf can add a probe on kernel module which has not been loaded yet.
> Current implementation finds module name from path. But if filename
> is different from actual module name then perf fails to register
> probe while loading module because of mismatch in names. For example,
> samples/kobject/kobject-example.ko is loaded as kobject_example.
> 
> Before applying patch:
> 
>   $ sudo ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show
> Added new event:
>   probe:foo_show   (on foo_show in kobject-example)
> 
> You can now use it in all perf tools, such as:
> 
> perf record -e probe:foo_show -aR sleep 1
> 
>   $ cat /sys/kernel/debug/tracing/kprobe_events
> p:probe/foo_show kobject-example:foo_show
> 
>   $ insmod kobject-example.ko
> 
>   $ lsmod
> Module  Size  Used by
> kobject_example16384  0
> 
>   Generate read to /sys/kernel/kobject_example/foo while recording data
>   with below command
>   $ sudo ./perf record -e probe:foo_show -a
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.093 MB perf.data ]
> 
>   $./perf report --stdio -F overhead,comm,dso,sym
> Error:
> The perf.data.old file has no samples!
> 
> After applying patch:
> 
>   $ sudo ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show
> Added new event:
>   probe:foo_show   (on foo_show in kobject_example)
> 
> You can now use it in all perf tools, such as:
> 
> perf record -e probe:foo_show -aR sleep 1
> 
>   $ sudo cat /sys/kernel/debug/tracing/kprobe_events
> p:probe/foo_show kobject_example:foo_show
> 
>   $ insmod kobject-example.ko
> 
>   $ lsmod
> Module  Size  Used by
> kobject_example16384  0
> 
>   Generate read to /sys/kernel/kobject_example/foo while recording data
>   with below command
>   $ sudo ./perf record -e probe:foo_show -a
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.097 MB perf.data (8 samples) ]
> 
>   $ sudo ./perf report  --stdio -F overhead,comm,dso,sym
> ...
> # Samples: 8  of event 'probe:foo_show'
> # Event count (approx.): 8
> #
> # Overhead  Command  Shared Object  Symbol
> #   ...  .  
> #
>100.00%  cat  [kobject_example]  [k] foo_show
> 

Looks good to me :)

Acked-by: Masami Hiramatsu 

Thank you!

> Signed-off-by: Ravi Bangoria 
> ---
>  tools/perf/util/probe-event.c | 19 +--
>  1 file changed, 5 insertions(+), 14 deletions(-)
> 
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index d58de20..26803e1 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -642,32 +642,23 @@ static int add_module_to_probe_trace_events(struct 
> probe_trace_event *tevs,
>   int ntevs, const char *module)
>  {
>   int i, ret = 0;
> - char *tmp;
> + char *mod_name = NULL;
>  
>   if (!module)
>   return 0;
>  
> - tmp = strrchr(module, '/');
> - if (tmp) {
> - /* This is a module path -- get the module name */
> - module = strdup(tmp + 1);
> - if (!module)
> - return -ENOMEM;
> - tmp = strchr(module, '.');
> - if (tmp)
> - *tmp = '\0';
> - tmp = (char *)module;   /* For free() */
> - }
> + mod_name = find_module_name(module);
>  
>   for (i = 0; i < ntevs; i++) {
> - tevs[i].point.module = strdup(module);
> + tevs[i].point.module =
> + strdup(mod_name ? mod_name : module);
>   if (!tevs[i].point.module) {
>   ret = -ENOMEM;
>   break;
>   }
>   }
>  
> - free(tmp);
> + free(mod_name);
>   return ret;
>  }
>  
> -- 
> 1.9.1
> 


-- 
Masami Hiramatsu

[PATCH 2/2] perf probe: Fix offline module name missmatch issue

2016-04-26 Thread Ravi Bangoria 
Perf can add a probe on kernel module which has not been loaded yet.
Current implementation finds module name from path. But if filename
is different from actual module name then perf fails to register
probe while loading module because of mismatch in names. For example,
samples/kobject/kobject-example.ko is loaded as kobject_example.

Before applying patch:

  $ sudo ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show
Added new event:
  probe:foo_show   (on foo_show in kobject-example)

You can now use it in all perf tools, such as:

perf record -e probe:foo_show -aR sleep 1

  $ cat /sys/kernel/debug/tracing/kprobe_events
p:probe/foo_show kobject-example:foo_show

  $ insmod kobject-example.ko

  $ lsmod
Module  Size  Used by
kobject_example16384  0

  Generate read to /sys/kernel/kobject_example/foo while recording data
  with below command
  $ sudo ./perf record -e probe:foo_show -a
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.093 MB perf.data ]

  $./perf report --stdio -F overhead,comm,dso,sym
Error:
The perf.data.old file has no samples!

After applying patch:

  $ sudo ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show
Added new event:
  probe:foo_show   (on foo_show in kobject_example)

You can now use it in all perf tools, such as:

perf record -e probe:foo_show -aR sleep 1

  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
p:probe/foo_show kobject_example:foo_show

  $ insmod kobject-example.ko

  $ lsmod
Module  Size  Used by
kobject_example16384  0

  Generate read to /sys/kernel/kobject_example/foo while recording data
  with below command
  $ sudo ./perf record -e probe:foo_show -a
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.097 MB perf.data (8 samples) ]

  $ sudo ./perf report  --stdio -F overhead,comm,dso,sym
...
# Samples: 8  of event 'probe:foo_show'
# Event count (approx.): 8
#
# Overhead  Command  Shared Object  Symbol
#   ...  .  
#
   100.00%  cat  [kobject_example]  [k] foo_show

Signed-off-by: Ravi Bangoria 
---
 tools/perf/util/probe-event.c | 19 +--
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index d58de20..26803e1 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -642,32 +642,23 @@ static int add_module_to_probe_trace_events(struct 
probe_trace_event *tevs,
int ntevs, const char *module)
 {
int i, ret = 0;
-   char *tmp;
+   char *mod_name = NULL;
 
if (!module)
return 0;
 
-   tmp = strrchr(module, '/');
-   if (tmp) {
-   /* This is a module path -- get the module name */
-   module = strdup(tmp + 1);
-   if (!module)
-   return -ENOMEM;
-   tmp = strchr(module, '.');
-   if (tmp)
-   *tmp = '\0';
-   tmp = (char *)module;   /* For free() */
-   }
+   mod_name = find_module_name(module);
 
for (i = 0; i < ntevs; i++) {
-   tevs[i].point.module = strdup(module);
+   tevs[i].point.module =
+   strdup(mod_name ? mod_name : module);
if (!tevs[i].point.module) {
ret = -ENOMEM;
break;
}
}
 
-   free(tmp);
+   free(mod_name);
return ret;
 }
 
-- 
1.9.1

[PATCH 2/2] perf probe: Fix offline module name missmatch issue

2016-04-26 Thread Ravi Bangoria 
Perf can add a probe on kernel module which has not been loaded yet.
Current implementation finds module name from path. But if filename
is different from actual module name then perf fails to register
probe while loading module because of mismatch in names. For example,
samples/kobject/kobject-example.ko is loaded as kobject_example.

Before applying patch:

  $ sudo ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show
Added new event:
  probe:foo_show   (on foo_show in kobject-example)

You can now use it in all perf tools, such as:

perf record -e probe:foo_show -aR sleep 1

  $ cat /sys/kernel/debug/tracing/kprobe_events
p:probe/foo_show kobject-example:foo_show

  $ insmod kobject-example.ko

  $ lsmod
Module  Size  Used by
kobject_example16384  0

  Generate read to /sys/kernel/kobject_example/foo while recording data
  with below command
  $ sudo ./perf record -e probe:foo_show -a
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.093 MB perf.data ]

  $./perf report --stdio -F overhead,comm,dso,sym
Error:
The perf.data.old file has no samples!

After applying patch:

  $ sudo ./perf probe -m /linux/samples/kobject/kobject-example.ko foo_show
Added new event:
  probe:foo_show   (on foo_show in kobject_example)

You can now use it in all perf tools, such as:

perf record -e probe:foo_show -aR sleep 1

  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
p:probe/foo_show kobject_example:foo_show

  $ insmod kobject-example.ko

  $ lsmod
Module  Size  Used by
kobject_example16384  0

  Generate read to /sys/kernel/kobject_example/foo while recording data
  with below command
  $ sudo ./perf record -e probe:foo_show -a
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.097 MB perf.data (8 samples) ]

  $ sudo ./perf report  --stdio -F overhead,comm,dso,sym
...
# Samples: 8  of event 'probe:foo_show'
# Event count (approx.): 8
#
# Overhead  Command  Shared Object  Symbol
#   ...  .  
#
   100.00%  cat  [kobject_example]  [k] foo_show

Signed-off-by: Ravi Bangoria 
---
 tools/perf/util/probe-event.c | 19 +--
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index d58de20..26803e1 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -642,32 +642,23 @@ static int add_module_to_probe_trace_events(struct 
probe_trace_event *tevs,
int ntevs, const char *module)
 {
int i, ret = 0;
-   char *tmp;
+   char *mod_name = NULL;
 
if (!module)
return 0;
 
-   tmp = strrchr(module, '/');
-   if (tmp) {
-   /* This is a module path -- get the module name */
-   module = strdup(tmp + 1);
-   if (!module)
-   return -ENOMEM;
-   tmp = strchr(module, '.');
-   if (tmp)
-   *tmp = '\0';
-   tmp = (char *)module;   /* For free() */
-   }
+   mod_name = find_module_name(module);
 
for (i = 0; i < ntevs; i++) {
-   tevs[i].point.module = strdup(module);
+   tevs[i].point.module =
+   strdup(mod_name ? mod_name : module);
if (!tevs[i].point.module) {
ret = -ENOMEM;
break;
}
}
 
-   free(tmp);
+   free(mod_name);
return ret;
 }
 
-- 
1.9.1