Date: Wed, 8 Apr 2009 09:01:50 -0400
From: "Frank Ch. Eigler" <fche@redhat.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>, Masami Hiramatsu <mhiramat@redhat.com>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
       Jim Keniston <jkenisto@us.ibm.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Vegard Nossum <vegard.nossum@gmail.com>,
       "H. Peter Anvin" <hpa@zytor.com>, Steven Rostedt <rostedt@goodmis.org>,
       Avi Kivity <avi@redhat.com>,
       Satoshi Oshima <satoshi.oshima.fk@hitachi.com>,
       systemtap-ml <systemtap@sources.redhat.com>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PROTO][PATCH -tip 0/7] kprobes: support jump optimization on x86
Message-ID: <20090408130150.GC13827@redhat.com>
References: <49DA7702.5030308@redhat.com> <20090408011743.GB5977@nowhere> <49DC0307.6080107@redhat.com> <20090408101056.GA14482@elte.hu> <20090408110602.GA14687@one.firstfloor.org>
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On Wed, Apr 08, 2009 at 01:06:02PM +0200, Andi Kleen wrote:
> [...]
> > 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.

On a machine with lots of free RAM, gcc will not hold itself back.  On
my home server, a 40000-kprobe script compiled (pass 4) in about 4
seconds using about 200MB RAM.

- FChE
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