Re: [PATCH 2/3] ring-buffer: make lockless

From: Steven Rostedt
Date: Wed Jul 08 2009 - 17:17:11 EST



On Wed, 8 Jul 2009, Mathieu Desnoyers wrote:

> * Steven Rostedt (rostedt@xxxxxxxxxxx) wrote:
> > From: Steven Rostedt <srostedt@xxxxxxxxxx>
> >
> > This patch converts the ring buffers into a completely lockless
> > buffer recording system. The read side still takes locks since
> > we still serialize readers. But the writers are the ones that
> > must be lockless (those can happen in NMIs).
>
> Hi Steven,
>
> Have you started modeling this scheme with Promela as I previously
> discussed with you ? Paul McKenney did a lot of nice papers on the
> topic, and given the complexity level of this lockless buffering
> algorithm, I'd be much more comfortable if it was formally verified. The
> idea here is to make sure we don't start an endless bug-chasing hunt as
> trace buffers gets more exposure to various workloads.

I would when I get time. Too many things on my plate at the moment. But
I do constantly run my ring-buffer-benchmark module, which highly stresses
the buffer. I have not had to fix a bug in it for a long time, and nothing
that needed a design change.

I'll try it out (or better yet, maybe someone else will) when I get more
time.

-- Steve

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