Re: blktrace ftrace plugin, was Re: Receive side performance issuewith multi-10-GigE and NUMA

[Arnaldo Carvalho de Melo]

Em Thu, Aug 27, 2009 at 11:14:54AM +0200, Jens Axboe escreveu:
> On Thu, Aug 27 2009, Ingo Molnar wrote:
> > 
> > * Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:
> > 
> > > On Wed, Aug 26 2009, Christoph Hellwig wrote:
> > > > On Wed, Aug 26, 2009 at 10:40:27PM +0200, Ingo Molnar wrote:
> > > > > We are also converting non-trivial plugins to generic tracepoints. A 
> > > > > recent example are the system call tracepoints, but we also 
> > > > > converted blktrace and kmemtrace to generic tracepoints.
> > > > 
> > > > On something semi-related: Any reason to keep the blktrace 
> > > > ftrace plugin around?  I don't think there's much point in it.  
> > > > It only got added in 2.6.29, and all the blktrace tooling just 
> > > > uses the legacy ioctls.  All new uses should just use the 
> > > > TRACE_EVENT output.
> > > 
> > > Lets kill it.
> > 
> > Agreed.
> > 
> > I think we should keep the relayfs and ioctl compatibility bits 
> > though: blktrace has a mature user-space environment with many
> > years of installed base.
> > 
> > We could even move those bits back to block/blktrace_compat.c or so 
> > (after the ftrace plugin bits are removed), to make sure it's nicely 
> > isolated.
> > 
> > What do you think?
> 
> Of course, we have to retain the ioctl/relayfs interface, it's been in
> use for years. Keeping those out of the other trace/ bits sounds sane.

Yeah, I wonder tho if we couldn't somehow use the ring buffer
infrastructure in such a way as to provide the debugfs visible interface
provided by relayfs, IIRC systemtap is doing such a move too.

- Arnaldo
--
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/