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Re: [RFC]-Approaches to user space probes
- From: "Frank Ch. Eigler" <fche at redhat dot com>
- To: "Keshavamurthy, Anil S" <anil dot s dot keshavamurthy at intel dot com>
- Cc: systemtap at sources dot redhat dot com
- Date: Wed, 1 Feb 2006 21:07:47 -0500
- Subject: Re: [RFC]-Approaches to user space probes
- References: <44BDAFB888F59F408FAE3CC35AB4704102E87148@orsmsx409>
Hi -
anil.s.keshavamurthy wrote:
> [...] I am not an expert in Java or Java probes, but before we lock
> down this approach I am suggesting that if possible we get feedback
> from JVM gurus too.
OK, but to involve them at this stage, we have to first formulate the
issue in a form they can understand. Beyond asking them to add a few
hooks into their various interpreters (similarly to dtrace), how do
you think they might be impacted?
> [...] having a counter to count the missed probe does not solve the
> problem here.
Which problem? That this can occur (with some low probability?)?
That it may be difficult to detect after occurrence? That it may
be hard for a user to work around (rerunning may not work)?
> [...] In other words we should not see rp->nmissed > 0, however it
> is okay to for rp->kp.nmissed > 0.
While we may *prefer* not to see any nmissed > 0, how bad do you think
the consequences are if we do miss a few? What are the odds?
- FChE