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Date: Wed, 24 Sep 2008 13:56:38 -0700
From: "Martin Bligh" <mbligh@google.com>
To: "Linus Torvalds" <torvalds@linux-foundation.org>
Subject: Re: [RFC PATCH 1/3] Unified trace buffer
Cc: "Peter Zijlstra" <peterz@infradead.org>,
       "Steven Rostedt" <rostedt@goodmis.org>, linux-kernel@vger.kernel.org,
       "Ingo Molnar" <mingo@elte.hu>, "Thomas Gleixner" <tglx@linutronix.de>,
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       "Mathieu Desnoyers" <compudj@krystal.dyndns.org>,
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       "David Wilder" <dwilder@us.ibm.com>, hch@lst.de,
       "Tom Zanussi" <zanussi@comcast.net>,
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> On Wed, 24 Sep 2008, Martin Bligh wrote:
>>
>> If we use 32 bits instead of 27, then the timestamp events are only
>> about once per second, which is probably fine for overhead ... ?
>
> You'd have them ONCE IN A BLUE MOON.
>
> If there is nothing going on, you don't need the timestamps at all.

Yeah, you're right - we can just mark it dirty, and 'pre-log' the timestamp
events when someone calls a reserve and we haven't logged anything
for more time than we can store. Did not think of that. Was only 5 bits
for us, not an extra 37, but still, is much better.

Is a 5-bit event id generic enough though?