From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from co9outboundpool.messaging.microsoft.com (co9ehsobe002.messaging.microsoft.com [207.46.163.25]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "MSIT Machine Auth CA 2" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 2C2442C00BD for ; Tue, 29 Oct 2013 04:52:18 +1100 (EST) Message-ID: <1382982727.3410.1.camel@snotra.buserror.net> Subject: Re: [PATCH] [RFC] Emulate "lwsync" to run standard user land on e500 cores From: Scott Wood To: James Yang Date: Mon, 28 Oct 2013 12:52:07 -0500 In-Reply-To: References: <1382081880-6666-1-git-send-email-wd@denx.de> <39CCEB38-1D9B-4918-B8F4-148D4E90FE21@kernel.crashing.org> <1382523314.3926.21.camel@aoeu.buserror.net> <1382607919.9395.56.camel@pasglop> <6BFC8EB0-1A75-41C3-985A-E3ED14846710@kernel.crashing.org> <1382697373.3926.36.camel@aoeu.buserror.net> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Cc: linuxppc-dev@lists.ozlabs.org, Wolfgang Denk List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2013-10-25 at 10:25 -0500, James Yang wrote: > On Fri, 25 Oct 2013, Scott Wood wrote: > > > Has anyone measured how much this slows things down with a typical > > userspace? > > Not a measurement of the patch in question but an older similar patch > on 3.0.51 (8572 running Debian 5.0.3): > > $ ./test-lwsync > cycles per emulated lwsync = 371 > cycles per sync = 36 My point was more to find out how often a typical userspace executes these instructions. From Wolfgang's e-mail it seems the answer is not very often. -Scott