Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761458AbZD1OZb (ORCPT ); Tue, 28 Apr 2009 10:25:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755483AbZD1OZW (ORCPT ); Tue, 28 Apr 2009 10:25:22 -0400 Received: from mx2.redhat.com ([66.187.237.31]:48913 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753580AbZD1OZV (ORCPT ); Tue, 28 Apr 2009 10:25:21 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20090329203118.GA14005@linux.vnet.ibm.com> References: <20090329203118.GA14005@linux.vnet.ibm.com> <20090203183426.GA14409@linux.vnet.ibm.com> To: paulmck@linux.vnet.ibm.com Cc: dhowells@redhat.com, linux-kernel@vger.kernel.org, mingo@elte.hu, akpm@linux-foundation.org, niv@us.ibm.com, dvhltc@us.ibm.com, lethal@linux-sh.org, kernel@wantstofly.org, matthew@wil.cx Subject: Re: [PATCH] v3 RCU: the bloatwatch edition Date: Tue, 28 Apr 2009 15:24:14 +0100 Message-ID: <13990.1240928654@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1406 Lines: 37 Paul E. McKenney wrote: > This patch is a version of RCU designed for (!SMP && EMBEDDED) > provided as a proof of concept of a small-footprint RCU implementation. > In particular, the implementation of synchronize_rcu() is extremely > lightweight and high performance. It passes rcutorture testing in each > of the four relevant configurations (combinations of NO_HZ and PREEMPT) > on x86. This saves about 900 bytes compared to Classic RCU, and a > couple kilobytes compared to Hierarchical RCU: On FRV, CLASSIC_RCU: text data bss dec hex filename 2616 184 0 2800 af0 kernel/rcuclassic.o 884 32 20 936 3a8 kernel/rcupdate.o TREE_RCU: 3940 328 0 4268 10ac kernel/rcutree.o 884 32 20 936 3a8 kernel/rcupdate.o TINY_RCU: 1152 32 0 1184 4a0 kernel/rcutiny.o 836 32 20 888 378 kernel/rcupdate.o It works on my FRV board. Possibly TINY_RCU could be shrunk a bit more by a judicious bit of inlining of some of the very small functions. Acked-by: David Howells -- 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/