Messages in this thread | | | Date | Mon, 06 Sep 2010 20:55:54 +0300 | From | Avi Kivity <> | Subject | Re: disabling group leader perf_event |
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On 09/06/2010 06:47 PM, Ingo Molnar wrote: > >> The actual language doesn't really matter. > There are 3 basic categories: > > 1- Most (least abstract) specific code: a block of bytecode in the form > of a simplified, executable, kernel-checked x86 machine code block - > this is also the fastest form. [yes, this is actually possible.]
Do you then recompile it? x86 is quite unpleasant.
> 2- Least specific (most abstract) code: A subset/sideset of C - as it's > the most kernel-developer-trustable/debuggable form. > > 3- Everything else little more than a dot on the spectrum between the > first two points. > > I lean towards #2 - but #1 looks interesting too. #3 is distinctly > uninteresting as it cannot be as fast as #1 and cannot be as convenient > as #2.
Curious - how do you guarantee safety of #1 or even #2? Can you point me to any research?
Everything I'm aware of is bytecode with explicit measures to prevent forged pointers, but I admit I've spent no time on it. It's interesting stuff, though.
-- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.
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