RE: tracepoints

Newman, Mark (N-Superior Technical Resource Inc)
2003-10-02T14:20:08Z

Hi Saravan -

Lockheed does not use HP-GDB. However in the past something very much
like tracepoints has been used as part of the integration of large
systems. That was done at enormous cost. I am looking at a low cost
mechanism for doing it in the future. (I wrote the earlier
implementations and have written a current gdb/gdbserver
implementation).

I don't understand the desire to have tracepoints in a native
environment. Tracepoints are designed to be non(read
minimally)-invasive. They are designed to be sensitive to Heisenberg.
That means that they perturb system operation as little as possible
while collecting data.

When we have used this type of functionality the idea was to set up a
situation, collect information, wait for some event to occur, and then
go in and look and see what happened. That event may or may not be a
planned event. It was used less to debug programs and more to debug
systems. It was an integration tool (although it has been used to debug
logic problems) that allows one to see what happens in the dirty
environment of the real world. Not in the clean environment of a test
case.

The only real differences I see between what we used in the past and
Introspect is the fact that Introspect collects data in the target
memory and the target is halted when the data is being analyzed. The
former means to me that if I am not careful the data can have rolled off
the end of a queue before I look at it or perhaps the target locked and
I can't get at the collected data. The latter violates the principle
espoused by Heisenberg.

Please let me know what your feelings are. This idea has been cobbed
together by a relatively small group of people in the past. It needs to
have the scrutiny of many talented people applied to it.

Mark Newman

-----Original Message-----
From: Saravanan [mailto:pes@india.hp.com]
Sent: Wednesday, October 01, 2003 7:34 AM
To: Newman, Mark (N-Superior Technical Resource Inc)
Cc: jimb@redhat.com; Johnson Samuel
Subject: Re: tracepoints

Hi ,
I am Saravanan working for supporting HP-GDB/WDB product. I am doing
a feasibility
study of supporting native tracepoints in HP-GDB/WDB.

Does Lockheed use HP-GDB/WDB for their debugging? If yes, would it
help if we put this
feature in HP-GDB/WDB ?

Regards,
Saravanan

>
> Saravanan
>
> Lockheed is investing money in tracepoints. I have not been able to
get on the GDB mailing list's to indicate our interest in supporting
them although I have spent time discussing an implementation with people
at Redhat.
>
> If you would like to work towards a common goal please let me know
>
>
Mark Newman