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Date: Fri, 19 Sep 2008 14:42:58 -0700
From: Randy Dunlap <randy.dunlap@oracle.com>
To: "Martin Bligh" <mbligh@google.com>
Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
       "Linus Torvalds" <torvalds@linux-foundation.org>,
       "Thomas Gleixner" <tglx@linutronix.de>,
       "Mathieu Desnoyers" <compudj@krystal.dyndns.org>,
       "Steven Rostedt" <rostedt@goodmis.org>, od@novell.com,
       "Frank Ch. Eigler" <fche@redhat.com>
Subject: Re: Unified tracing buffer
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On Fri, 19 Sep 2008 14:33:42 -0700 Martin Bligh wrote:

> STORAGE
> -------
> 
> We will support multiple buffers for different tracing systems, with
> separate names, event id spaces.
> Event ids are 16 bit, dynamically allocated.

What are these (like)?

> A "one line of text" print function will be provided for each event,
> or use the default (probably hex printf)
> Will provide a "flight data recorder" mode, and a "spool to disk" mode.
> 
> Circular buffer per cpu, protected by per-cpu spinlock_irq
> Word aligned records.

Arch-specific "word"?
or some fixed-size-for-all-systems (so that trace buffers can be
shared/used on other systems?)  Preferably the latter.


> Variable record length, header will start with length record.
> Timestamps in fixed timebase, monotonically increasing (across all CPUs)

what timestamp resolution?


---
~Randy