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Date: Tue, 30 Sep 2008 15:43:45 -0400 (EDT)
From: Steven Rostedt <rostedt@goodmis.org>
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To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
cc: Martin Bligh <mbligh@google.com>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
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       "Frank Ch. Eigler" <fche@redhat.com>,
       Andrew Morton <akpm@linux-foundation.org>, hch@lst.de,
       David Wilder <dwilder@us.ibm.com>, Tom Zanussi <zanussi@comcast.net>
Subject: Re: [RFC PATCH] LTTng relay buffer allocation, read, write
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On Tue, 30 Sep 2008, Mathieu Desnoyers wrote:
> 
> You are actually using them to put redundant information that could be
> encoded differently and thus save 4 bits per event records, more or less
> what will be needed by most tracers (15 IDs, 1 reserved for an extended
> ID field).

I really like the idea of keeping the tracer event ids out of the ring 
buffer logic.

> 
> So the fact that you use them does not mean they are really required,
> and I don't think such duplicated information actually makes things more
> solid. Maybe just more obscure ?

Well, at least for version 1 these bits stay. I already found two bugs by 
hitting the event padding when the size said it should not have. This 
redundant information makes me feel a bit more cozy when they match.

-- Steve