Re: [PATCHv11 2.6.36-rc2-tip 5/15] 5: uprobes: Uprobes(un)registration and exception handling.

From: Mathieu Desnoyers
Date: Tue Sep 07 2010 - 12:47:55 EST


* Srikar Dronamraju (srikar@xxxxxxxxxxxxxxxxxx) wrote:
> > On Mon, Sep 06, 2010 at 11:16:42PM +0530, Srikar Dronamraju wrote:
[...]
> >
> > Which btw, brings up two more issues, one in uprobes and one in perf.
> > For one even in userspace I think the dynamic probes will really just
> > be the tip of the iceberg and we'll get more bang for the buck from
> > static traces, which is something that's no supported in uprobes yet.
> > As a start supporting the dtrace-style sdt.h header would be a great
> > help, and then we can decide if we need somthing even better on top.
>
> Yes, Static tracing using dtrace style sdt.h is a cool thing to do.
> Already SystemTap has this facility. However I think its probably
> better done at perf user interface level.

We currently have this feature in UST. We're adding "markers" into the
applications, and a UST daemon talks with an in-process library helper thread to
enable/disable markers and control tracing over unix sockets.

We're currently in the process of moving from markers to the
TRACE_EVENT()+tracepoints infrastructure.

Thanks,

Mathieu

>
> The way I look at it is perf probe decodes the static markers and asks
> uprobes to place probepoints over there.
> Do you see a different approach? If yes can you tell what you were
> looking at?

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
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