Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754752Ab2EVNjN (ORCPT ); Tue, 22 May 2012 09:39:13 -0400 Received: from flusers.ccur.com ([173.221.59.2]:45420 "EHLO gamx.iccur.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752184Ab2EVNjL (ORCPT ); Tue, 22 May 2012 09:39:11 -0400 Date: Tue, 22 May 2012 09:38:58 -0400 From: Joe Korty To: Andi Kleen Cc: "stasn77@gmail.com" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] port jRCU from 3.3 to 3.4 Message-ID: <20120522133858.GA17487@tsunami.ccur.com> Reply-To: Joe Korty References: <20120521184528.GA4145@tsunami.ccur.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1105 Lines: 25 On Mon, May 21, 2012 at 06:57:44PM -0400, Andi Kleen wrote: > Joe Korty writes: > > + * > > + * jRCU assumes that the frames are large enough that architecture barrier > > + * operations performed in one frame have fully completed by the start of > > + * the next. This period is presumed to be in the tens of microseconds, so > > + * it may not be wise to run jRCU at a frame rate under 100 usecs. > > This sounds like a very dangerous assumption. Yeah, I may have to go to a spin lock. Easy to do, but I didn't want the serialization that results. I figured that with a frame rate of 20 - 1000 Hz it wasn't necessary. And of course I may not have fully understood all the nuances of barriers and the memory model. After all, spin locks work using pretty much the same techniques and they don't suffer from any need to delay. Joe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/