On Wed, 2010-11-10 at 19:24 +0100, Peter Zijlstra wrote:
quoted text
> On Wed, 2010-11-10 at 13:05 -0500, Steven Rostedt wrote:
> > 
> > Peter said at LPC that the perf buffering system was not designed to
> > handle high speed tracing. But he also said he does not like the way the
> > ftrace buffering works. 
> 
> You're not very good at listening,

Or I'm not good at rephrasing, but both are probably true ;-)


quoted text
>  I said the perf infrastructure and
> event handling mechanism isn't geared towards full throughput but
> instead on sampling.

OK, not the buffering, but the infrastructure. That's not much of a
difference to this topic. Which is about the ABI which includes all from
the user to the buffer.

quoted text
> 
> There is lots of code between getting the event and landing it in the
> buffer. The buffer itself is perfectly suited for high speed low
> overhead stuffs, the perf data format possibly not because its not
> bitfield happy.

Well, we need to separate out the buffer in perf regardless, since it is
very entwined in the code. Does it now support flight recorder mode?

-- Steve


--
unsubscribe notice
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/