RE: Tracing Requirements (was: [RFC/Requirements/Design] h/w error reporting)

[Steven Rostedt <rostedt@goodmis.org>]

On Wed, 2010-11-10 at 16:06 -0500, Steven Rostedt wrote:

> > Perhaps you could explain the use cases of your "flight recorder",
> > because it seems that the name doesn't fit exactly, and this is
> > causing me (and maybe others) some confusion.

> 2) overwrite mode (flight recorder) - when the writer reaches the
> reader, it pushes the reader forward, and writes the new events over the
> old ones. This way, new events are always existent, where as old events
> are lost.

Ah, I forgot to mention use cases.

Even when recording a trace (lots of data, so it is saved to disk and
not all in kernel memory) I like to know that if something happens and
disables the trace, I have all the trace information up to the point of
failure.

With producer/consumer mode, you risk the reader being late and the
events in the trace that led up to failure (or any other anomaly) were
dropped.

-- Steve