Re: disabling group leader perf_event

From: Pavel Machek
Date: Sun Sep 12 2010 - 15:14:43 EST


On Sun 2010-09-12 20:48:43, Ingo Molnar wrote:
>
> * Avi Kivity <avi@xxxxxxxxxx> wrote:
>
> > On 09/12/2010 08:46 AM, Pavel Machek wrote:
> > > 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.]
> > >Well... if we want to be a bit x86-entric.... can we just reuse ACPI
> > >interpretter?
> >
> > I hope this was a joke, ACPI won the academy awards for ugliness,
> > ..., bad specification, non-generality, and

As did i386 instruction set :-).

> It also combines the worst of the two worlds: it's the most specific
> type of code (almost like assembly), but has a very slow interpreter.
>
> With 'x86 bytecode' the main (and pretty much only) point is to be able
> to execute the code as-is, once checked.
>
> But, as i explained it before, i only consider it a theoretical
> possibility and i think that abstract code (such as ASCII text C source
> code) is a better solution.

Compiler in kernel?

I'm not sure I like that one. Yes, ACPI interpreter is slow, but it is
simple, already in kernel, and there are already tools to compile into
it...

While it may be ugly, I believe it is better than either i386
verifier, compiler in the kernel, or yet another interpretter...

Pavel

--
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