Re: [rfc] Describe events in a structured way via sysfs

[Lin Ming <ming.m.lin@intel.com>]

On Tue, 2010-06-22 at 15:39 +0800, Johannes Berg wrote:
> On Tue, 2010-06-22 at 09:33 +0200, Johannes Berg wrote:
> 
> > > > > net/wlan0/events/
> > > > > net/waln1/events/
> > > > > ....
> > > > > net/walnN/events/
> > > > 
> > > > That's not appropriate either though since you may have multiple network
> > > > interfaces on the same hardware :)
> > > 
> > > Doesn't net/wlan0...wlanN mean multiple network interfaces on the same
> > > hardware?
> > 
> > Yes, but the trace points aren't per network interface but rather per
> > hardware piece.
> 
> Which really just means that whoever writes the tracepoint needs to
> provide a struct device for where to put it (at least in the case of
> driver tracepoints), and then ideally some description of the device
> also gets put into the ringbuffer.

I'm not familiar with tracepoint code. Correct me if I'm wrong.
Do you mean that, for example, if iwlwifi_dev_ioread32 event is traced,
then the "device" info will get put into the ftrace ringbuffer?

> 
> Assuming you actually want to have the event show up in sysfs twice if
> it has multiple producers? I'd like that, it would make sense for a lot
> of cases since you might only care about one of the producers.

Yes, each producers has a "events" sysfs dir.

> 
> johannes
>