Re: [RFC][PROTO][PATCH -tip 0/7] kprobes: support jump optimization on x86

From: Andi Kleen
Date: Wed Apr 08 2009 - 07:03:59 EST


On Wed, Apr 08, 2009 at 12:10:56PM +0200, Ingo Molnar wrote:
>
> * Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
>
> > > But can we consider it as a small problem, assuming that kprobes
> > > are rarely intended for a massive use in once? I guess that
> > > usually, not a lot of functions are probed simultaneously.
> >
> > Hm, yes and no, systemtap may use massive kprobes, because it
> > supports "wildcard" probes. However, optimizing in default may be
> > acceptable.
>
> I'm curious: what is the biggest kprobe count you've ever seen, in
> the field? 1000? 10,000? 100,000? More?

The limit is iirc how much memory the gcc compiling the probes program
consumes before running out of swap space.

-Andi
--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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