Re: Linux Trace Toolkit

Werner Almesberger (
Sat, 7 Aug 1999 02:29:06 +0200

Karim Yaghmour wrote:
> The Linux Trace Toolkit enables it's user to know exactly
> what happened in a system at all times and why it happens.

Looks very interesting, particularly for debugging interactions among
groups of demons and/or the kernel. I've had a quick look at your
screen shots and the patch and the following things came to my mind:

- analysis looks a little cryptic and crowded. If you allocate more
vertical space per process, you can stack information vertically,
avoiding overlaps.
- the information available should really be similar to what strace
has. If your process is always just reading messages, then sending
a few, you really want to know what's inside of them. Manually
combining trace information obtained from multiple sources is tricky
and error-prone.
- I like the idea of tracing bottom half handlers; now it should also
trace interrupts
- you should be able to turn off part or all of the traceing at
compile time, such that you can use the same source tree for normal
- there should be a means for user processes to explicitly add data to
the trace (this can be trivial, without any extra system calls or
such: create a symlink /dev/tracer -> /dev/null; let process open it
and write user data to it; in trace analysis, you catch "/dev/tracer"
and label it as user data)

I haven't looked at it in detail, but do you also have text output ?
Sometimes you really want to run a few scripts over traces before they
become even remotely useful ...

Looks like a nice tool with a lot of potential.

- Werner

 / Werner Almesberger, ICA, EPFL, CH /

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