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Subject: Re: [RFC][PATCH v1 15/15] perf: export tracepoint events via
 sysfs: mac80211
From: Johannes Berg <johannes@sipsolutions.net>
To: Lin Ming <ming.m.lin@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>, Robert Richter <robert.richter@amd.com>,
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Date: Thu, 22 Jul 2010 13:21:42 +0200
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On Thu, 2010-07-22 at 19:18 +0800, Lin Ming wrote:
> mac80211 tracepoint events are exported like below,
> 
> /sys/class/ieee80211/events/
> |-- api_beacon_loss
> |   |-- config
> |   |-- type
> ....
> ....
> |-- drv_add_interface
> |   |-- config
> |   |-- type
> ....
> ....
> |-- stop_queue
> |   |-- config
> |   |-- type
> |-- wake_queue
> |   |-- config
> |   |-- type
> ---
>  drivers/base/class.c |   12 ++++++++++++
>  1 files changed, 12 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/base/class.c b/drivers/base/class.c
> index 8e231d0..57ada53 100644
> --- a/drivers/base/class.c
> +++ b/drivers/base/class.c
> @@ -19,6 +19,7 @@
>  #include <linux/slab.h>
>  #include <linux/genhd.h>
>  #include <linux/mutex.h>
> +#include <linux/perf_event.h>
>  #include "base.h"
>  
>  #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
> @@ -160,6 +161,14 @@ static void klist_class_dev_put(struct klist_node *n)
>  	put_device(dev);
>  }
>  
> +extern struct class ieee80211_class;
> +
> +static void class_sys_add_tp(struct kobject *class_kobj, struct class *cls)
> +{
> +	if (cls == &ieee80211_class)
> +		perf_sys_add_tp(class_kobj, "mac80211");
> +}
> +

Ick, what a bad hack! No way. And this really can't work anyway when
cfg80211 is a module. This is all messed up. The events should probably
be in /sys/class/ieee80211/phyX/ anyway.

johannes