Re: [patch 7/9] LTTng instrumentation - kernel

Rusty Russell
2009-03-25T01:13:46Z

On Wednesday 25 March 2009 05:03:13 Ingo Molnar wrote:
>
> (Rusty Cc:-ed - for the module.c tracepoints below)

Thanks, tho they look fine and non-intrusive to me.

> I believe that to have a complete picture of module usage, module
> refcount get/put events should be included as well, beyond the basic
> load/free events.
>
> These both have performance impact (a module get/put in a fastpath
> hurts scalability), and are informative in terms of establishing the
> module dependency graph.

A module_get()/put() should not hurt scalability at all! I went to great and
horrible lengths to ensure that was the case since the rewrite in 2.4.

But a module dependency graph et. al. would be kind of cool.

Thanks,
Rusty.