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Subject: Re: [RFC] [PATCH 1/7] User Space Breakpoint Assistance Layer (UBP)
From: Peter Zijlstra <peterz@infradead.org>
To: Avi Kivity <avi@redhat.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>, ananth@in.ibm.com,
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Date: Mon, 18 Jan 2010 13:24:05 +0100
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On Mon, 2010-01-18 at 14:17 +0200, Avi Kivity wrote:
> On 01/18/2010 02:13 PM, Pekka Enberg wrote:
> > So how big chunks of the address space are we talking here for uprobes?
> >    
> 
> That's for the authors to answer, but at a guess, 32 bytes per probe 
> (largest x86 instruction is 15 bytes), so 32 MB will give you a million 
> probes.  That's a piece of cake for x86-64, probably harder to justify 
> for i386.

Yeah, I'm aware of people turning off address space randomization to
gain more virtual space on i386, I'm pretty sure those folks aren't
going to be happy if we shrink it.

Let alone them trying to probe their app.