From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by monty-python.gnu.org with tmda-scanned (Exim 4.20) id 19NTXi-0007JZ-Kb for qemu-devel@nongnu.org; Wed, 04 Jun 2003 04:22:46 -0400 Received: from mail by monty-python.gnu.org with spam-scanned (Exim 4.20) id 19NTXh-0007J1-3D for qemu-devel@nongnu.org; Wed, 04 Jun 2003 04:22:45 -0400 Received: from alcor.imaginet.fr ([195.68.86.12]) by monty-python.gnu.org with esmtp (Exim 4.20) id 19NTVw-00071i-47 for qemu-devel@nongnu.org; Wed, 04 Jun 2003 04:20:56 -0400 Received: from free.fr (gw.netgem.com [195.68.2.34]) by alcor.imaginet.fr (8.11.6+Sun/8.8.8) with ESMTP id h548MSj15492 for ; Wed, 4 Jun 2003 10:22:28 +0200 (MET DST) Message-ID: <3EDDABC8.2080708@free.fr> Date: Wed, 04 Jun 2003 10:20:24 +0200 From: Fabrice Bellard MIME-Version: 1.0 Subject: Re: [Qemu-devel] performance of qemu References: <20030603201215.0ca4063b.jrydberg@night.trouble.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: List-Help: List-Post: List-Subscribe: , List-Archive: List-Unsubscribe: , To: qemu-devel@nongnu.org Johan Rydberg wrote: > Hi, > > has anyone of you guys (Fabrice et al) done any performance measurements of > QEMU? I'm particular intrested in the performance of functions that > set the condition codes. I plan to publish soon some benchmarks against bochs and native execution. > If I'm not mistaken, the condition codes is simulated using two values and > an operator specifying what type of insn that generated the condition codes. OK. > When is the full eflags register generated? In the epilogue of a translated > block, or when ever an insn/callback reads the eflag register? Only when an instruction really needs the full eflags register (such as pushf). > Is any optmization done in the case that two insns that kill the condition > codes? (example: two insns that kills the condition codes, but no insn between > them that uses it). Yes. Fabrice.