From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261376AbVFAMyP (ORCPT ); Wed, 1 Jun 2005 08:54:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261377AbVFAMyP (ORCPT ); Wed, 1 Jun 2005 08:54:15 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.146]:55255 "EHLO e6.ny.us.ibm.com") by vger.kernel.org with ESMTP id S261376AbVFAMyL (ORCPT ); Wed, 1 Jun 2005 08:54:11 -0400 Date: Wed, 1 Jun 2005 18:20:57 +0530 From: Dipankar Sarma To: William Lee Irwin III Cc: linux-kernel@vger.kernel.org, Al Viro , Andrew Morton Subject: Re: [rfc: patch 0/6] scalable fd management Message-ID: <20050601125056.GA4853@in.ibm.com> Reply-To: dipankar@in.ibm.com References: <20050530105042.GA5534@in.ibm.com> <20050601112520.GD20782@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050601112520.GD20782@holomorphy.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 01, 2005 at 04:25:20AM -0700, William Lee Irwin III wrote: > On Mon, May 30, 2005 at 04:20:42PM +0530, Dipankar Sarma wrote: > > I would appreciate if someone tests this on an arch without > > cmpxchg (sparc32??). I intend to run some more tests > > with preemption enabled and also on ppc64 myself. > > sparc32 SMP is not going to be a good choice for this. By and large > ll/sc -style architectures don't have explicit cmpxchg instructions so > ppc64 at least nominally fits the bill. SMP Alpha testing may also be > enlightening (as usual). Actually, I was talking about cmpxchg() primitive in the kernel, not necessarily the instruction. ppc64 has a cmpxchg() primitive based on LL/SC. For the archs that do not have cmpxchg(), rcuref_inc_lf() uses a hashed lock to serialize the reference count updates. It would be nice to see that code get a spin on real hardware. AFAICS, sparc32 fits the bill. Thanks Dipankar