From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753281Ab0ILTOi (ORCPT ); Sun, 12 Sep 2010 15:14:38 -0400 Received: from ksp.mff.cuni.cz ([195.113.26.206]:38752 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752211Ab0ILTOh (ORCPT ); Sun, 12 Sep 2010 15:14:37 -0400 Date: Sun, 12 Sep 2010 21:14:29 +0200 From: Pavel Machek To: Ingo Molnar Cc: Avi Kivity , Pekka Enberg , Tom Zanussi , Fr?d?ric Weisbecker , Steven Rostedt , Arnaldo Carvalho de Melo , Peter Zijlstra , linux-perf-users@vger.kernel.org, linux-kernel Subject: Re: disabling group leader perf_event Message-ID: <20100912191429.GA27440@elf.ucw.cz> References: <1283774045.1930.341.camel@laptop> <4C84D77B.6040600@redhat.com> <20100906124330.GA22314@elte.hu> <4C84E265.1020402@redhat.com> <20100906125905.GA25414@elte.hu> <4C850147.8010908@redhat.com> <20100906154737.GA4332@elte.hu> <20100912064612.GA1582@ucw.cz> <4C8D13CD.1060802@redhat.com> <20100912184843.GB11165@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100912184843.GB11165@elte.hu> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 2010-09-12 20:48:43, Ingo Molnar wrote: > > * Avi Kivity 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 -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html