Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964782AbWHHKHu (ORCPT ); Tue, 8 Aug 2006 06:07:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964784AbWHHKHt (ORCPT ); Tue, 8 Aug 2006 06:07:49 -0400 Received: from jaguar.mkp.net ([192.139.46.146]:43952 "EHLO jaguar.mkp.net") by vger.kernel.org with ESMTP id S964781AbWHHKHs (ORCPT ); Tue, 8 Aug 2006 06:07:48 -0400 To: Andi Kleen Cc: linux-kernel@vger.kernel.org, "Shai Fultheim (Shai@scalex86.org)" , pravin b shelar Subject: Re: [RFC] NUMA futex hashing References: <20060808070708.GA3931@localhost.localdomain> From: Jes Sorensen Date: 08 Aug 2006 06:07:47 -0400 In-Reply-To: Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.4 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 903 Lines: 17 >>>>> "Andi" == Andi Kleen writes: Andi> Jes Sorensen writes: >> Using that argument, all you need to do is to add the alignment >> ____cacheline_aligned_in_smp to the definition of struct >> futex_hash_bucket and the problem is solved, given that the >> internode cacheline in a NUMA system is defined to be the same as >> the SMP cacheline size. Andi> Yes but it would waste quite a lot of memory and cache. Wasted Andi> cache = slow. Compared to the extra level of indirection, I doubt it would be measurable. The cache space is barely wasted, we're talking approximately half a cacheline per futex hash bucket in use. Jes - 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/