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From: (Frank Ch. Eigler)
To: Andrew Cagney <>
Cc:, frysk <>
Subject: Re: my notes from the tracing workshop
Date: Fri, 01 Feb 2008 19:44:00 -0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <47A34AA2.5070404__28393.9727153212$1201883893$gmane$> (Andrew Cagney's message of "Fri, 01 Feb 2008 11:36:50 -0500")

Andrew Cagney <> writes:

> [...]
> Overview

Thank you!

> [...]
> The exceptions were SystemTAP and SensorPoint (Wind River) (and on the
> edge, frysk).  Both SystemTAP and SensorPoint and the same basic
> approaches.  SensorPoint did have a djprobe like mechanism working,
> and nested(?) probes (where you could specify the call chain required
> to trigger the probe - it worked by watching the functions and not by
> looking at backtraces); 

We will approximate this with the incoming optimizations for
"conditional probes".

> finally the ability to replace code on live systems.

I dunno when we try to address this aspect.

> Finaly, the big and positive thing on probes was that the kernel
> markers being accepted.  [...]
> This is where SystemTAP and SensorPoint stood out (I think :-).  Both
> have the ability to filter events before pushing them to the recorder.
> Using SystemTAP on the kernel markers should be a wicked combination.

Yeah, we hope so!

> [Can I assume that, when there's a marked up kernel, SystemTAP
> inserts jumps instead of traps?]

Indeed - or rather, the kernel marker API does this for us.  We become
just a client.  This was what my "integration platform for probing"
title line was all about - we can attach natively to multiple
instrumentation systems and present them in a cohesive manner.

> [...]
> "DB"
> There was a strong consensus that the "internal" format of the log
> data needed to be a fast light weight database; two vendors were using
> sqlite for instance (TPTP the eclipse tool didn't but I suspect will
> shortly).  [...]

This seems rather wacky.  If they're talking about gigabytes of trace
traffic, a little wee in-memory database is a reach.  If you need to
do declarative querying, then you need a real database with indexes
and whatnot.  If you just need a big ass array, use BerkeleyDB.  If
you just want strongly typed flat data on disk, go XML.  I wish I'd
been there - perhaps my perceptions could have been falsified.

> [...] What's the status of SystemTAP on the ARM?  [...]

I haven't run it personally, but others have (Eugene Teo for the Nokia
N800).  One difficulty appears to be finding a big enough ARM box to
self-host the kernel module build process, or else cross-compiling and

- FChE

       reply	other threads:[~2008-02-01 19:44 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <47A34AA2.5070404__28393.9727153212$1201883893$gmane$>
2008-02-01 19:44 ` Frank Ch. Eigler [this message]
2008-02-05 19:02   ` Andrew Cagney
2008-02-01 16:37 Andrew Cagney
2008-02-01 22:15 ` Elena Zannoni
2008-02-05 20:37 ` William Cohen
2008-03-03 16:57   ` Andrew Cagney

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