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

[Jens Axboe <jens.axboe@oracle.com>]

On Thu, Aug 27 2009, Ingo Molnar wrote:
> 
> * Jens Axboe <jens.axboe@oracle.com> 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.

-- 
Jens Axboe