From mboxrd@z Thu Jan 1 00:00:00 1970 From: fche@redhat.com (Frank Ch. Eigler) Subject: Re: linux-next: add utrace tree Date: Fri, 29 Jan 2010 13:13:47 -0500 Message-ID: References: <1264575134.4283.1983.camel@laptop> <20100127085442.GA28422@elte.hu> <1264643539.5068.62.camel@localhost.localdomain> <20100128085502.GA7713@elte.hu> <1264726768.4933.50.camel@localhost.localdomain> <20100129073907.GF14636@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <20100129073907.GF14636@elte.hu> (Ingo Molnar's message of "Fri, 29 Jan 2010 08:39:07 +0100") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: utrace-devel-bounces@redhat.com Errors-To: utrace-devel-bounces@redhat.com To: Ingo Molnar Cc: Stephen Rothwell , Kyle Moffett , Arnaldo Carvalho de Melo , Peter Zijlstra , Fr??d??ric Weisbecker , Oleg Nesterov , Steven Rostedt , LKML , Tom Tromey , linux-next@vger.kernel.org, "H. Peter Anvin" , utrace-devel@redhat.com, Linus Torvalds , Thomas Gleixner List-Id: linux-next.vger.kernel.org Ingo Molnar writes: > [...] So, to sum it up: utrace XOL, which is rather complex already, > needs even more complexity (which is not yet implemented) than the > much simpler common-case emulator approach i outlined, just to break > even with the performance of the much simpler approach. [...] Is it an uncontroversial claim that emulation of CISC instructions should perform better than their native execution, followed by an int3 (as in the simplest working scheme) or boosting (as done by kprobes)? >>From my experience with simulators, "simple" software emulation of cpus can be hundreds of times slower or worse than native execution. - FChE