Messages in this thread | | | Date | Wed, 8 Apr 2009 23:55:07 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: Multiple Tracers |
| |
Em Thu, Apr 09, 2009 at 10:11:48AM +0800, Li Zefan escreveu: > CC: Arnaldo Carvalho de Melo <acme@redhat.com> > > Ingo Molnar wrote: > > * Steven Whitehouse <swhiteho@redhat.com> wrote: > > > >> Hi, > >> > >> On Wed, 2009-04-08 at 15:53 +0200, Ingo Molnar wrote: > >>> * Steven Whitehouse <swhiteho@redhat.com> wrote: > >>> > >>>> Hi, > >>>> > >>>> A little while back I posted a RFC patch which added gfs2 glock > >>>> tracing to blktrace. There was a suggestion that I should look > >>>> instead at the generic tracing code and add a new tracer, but I've > >>>> come up with a couple of issues along the way. > >>>> > >>>> I think from what I can see that its only possible to run a single > >>>> tracer at once, so running blktrace (for example) would preclude > >>>> me from also tracing gfs2's glocks at the same time. Also, I can > >>>> see no mechanism by which I could ensure the sequencing between > >>>> the blktrace and glock traces other than exporting the blktrace > >>>> sequence number, even if running multiple tracers at the same time > >>>> was possible. > >>> There's a recent addition: the EVENT_TRACE() facility. Would that > >>> suit your purposes? > >>> > >>> Ingo > >> If I can get both blktrace and glock trace info from it, then yes. > >> I thought that the blktrace output went either via the original > >> relayfs path, or via its own tracer so that it wasn't possible to > >> use it and the event trace facility at the same time, unless I use > >> blktrace via relayfs. From what I've read I thought that probably > >> the relayfs interface for blktrace might eventually be removed in > >> favour of the generic tracing interface, but I'm not 100% sure of > >> that, so perhaps someone can confirm the plans in that area? > > > > Tom Zanussi (Cc:-ed) recently converted the blktrace tracepoints to > > I guess you mean Arnaldo <acme@redhat.com> ;)
Nope, Tom:
Message-Id: <1235725261.8512.89.camel@charm-linux>
> > a tracing framework - and i think much of that could be reused to > > add EVENT_TRACE() tracepoints to blktrace too. > > > > Tom, what's your take on this? > > > > In general, this is the direction we want to take: EVENT_TRACE() > > tracepoints that can be used in a generic way, in any tracer. > > > > Actually we've planed to do this, and for other tracers.
Yeah, being able to mix all kinds of tracers is the way to go.
- Arnaldo
| |