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Re: extent-patch and overview of what is supposed to follow

On Wed, Apr 06, 2011 at 12:14:27PM -0400, Thor Lancelot Simon wrote:
> On Wed, Apr 06, 2011 at 06:05:49PM +0200, Manuel Bouyer wrote:
> > 
> > - dtrace doesn't work everywhere (acutally I guess it's only x86, without
> >   Xen)
> If new code is going to be written to implement (or reimplement) debugging
> facilities I would strongly advocate that enhancing DTrace to work on more
> of our architectures would be a more productive use of that time.
> > - I'm not sure you want to have dtrace running on a production server.
> Um.  Can you explain why?  The probes are basically zero-cost (static
> probes, where they are explicitly placed in the source code, are
> __predict_false(); dynamic probes as would likely be use here are
> binary-patched into place).

Maybe I don't understand how dtrace works then, but I though installed/started
it generates a continous flow of events which are monitored, which have
to be retrieved from userland. Isn't it how this works ?

Manuel Bouyer <>
     NetBSD: 26 ans d'experience feront toujours la difference

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