Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262333AbVCPKXl (ORCPT ); Wed, 16 Mar 2005 05:23:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262334AbVCPKXl (ORCPT ); Wed, 16 Mar 2005 05:23:41 -0500 Received: from ms-smtp-01.nyroc.rr.com ([24.24.2.55]:3785 "EHLO ms-smtp-01.nyroc.rr.com") by vger.kernel.org with ESMTP id S262333AbVCPKXj (ORCPT ); Wed, 16 Mar 2005 05:23:39 -0500 Date: Wed, 16 Mar 2005 05:23:25 -0500 (EST) From: Steven Rostedt X-X-Sender: rostedt@localhost.localdomain Reply-To: rostedt@goodmis.org To: Ingo Molnar cc: Andrew Morton , rlrevell@joe-job.com, linux-kernel@vger.kernel.org Subject: Re: [patch 0/3] j_state_lock, j_list_lock, remove-bitlocks In-Reply-To: <20050316101209.GA16893@elte.hu> Message-ID: References: <20050315120053.GA4686@elte.hu> <20050315133540.GB4686@elte.hu> <20050316085029.GA11414@elte.hu> <20050316011510.2a3bdfdb.akpm@osdl.org> <20050316095155.GA15080@elte.hu> <20050316020408.434cc620.akpm@osdl.org> <20050316101209.GA16893@elte.hu> 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: 1177 Lines: 34 On Wed, 16 Mar 2005, Ingo Molnar wrote: > > * Andrew Morton wrote: > > > > ooh, I'd rather not. I spent an intense three days removing all the > > sleeping locks from ext3 (and three months debugging the result). > > Ended up gaining 1000% on 16-way. > > > > Putting them back in will really hurt the SMP performance. > > ah. Yeah. Sniff. > > if we gain 1000% on a 16-way then there's something really wrong about > semaphores (or scheduling) though. A semaphore is almost a spinlock, in > the uncontended case - and even under contention we really (should) just > spend the cycles that we'd spend spinning. There will be some > intermediate contention level where semaphores hurt, but 1000% sounds > truly excessive. > Could it possibly be that in the process of removing all the sleeping locks from ext3, that Andrew also removed a flaw in ext3 itself that is responsible for the 1000% improvement? -- Steve - 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/