From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) by kanga.kvack.org (Postfix) with ESMTP id BE2026B0037 for ; Wed, 27 Aug 2014 19:20:10 -0400 (EDT) Received: by mail-pa0-f47.google.com with SMTP id hz1so142951pad.20 for ; Wed, 27 Aug 2014 16:20:10 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id z3si3406734pdj.12.2014.08.27.16.20.08 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 27 Aug 2014 16:20:08 -0700 (PDT) Date: Wed, 27 Aug 2014 16:20:06 -0700 From: Andrew Morton Subject: Re: [PATCH 0/2] x86: Speed up ioremap operations Message-Id: <20140827162006.580e83d57696b5eba203b18c@linux-foundation.org> In-Reply-To: <53FE6690.80608@sgi.com> References: <20140827225927.364537333@asylum.americas.sgi.com> <20140827160610.4ef142d28fd7f276efd38a51@linux-foundation.org> <53FE6690.80608@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mike Travis Cc: mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com, msalter@redhat.com, dyoung@redhat.com, riel@redhat.com, peterz@infradead.org, mgorman@suse.de, linux-kernel@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org On Wed, 27 Aug 2014 16:15:28 -0700 Mike Travis wrote: > > > > >> There are two causes for requiring a restart/reload of the drivers. > >> First is periodic preventive maintenance (PM) and the second is if > >> any of the devices experience a fatal error. Both of these trigger > >> this excessively long delay in bringing the system back up to full > >> capability. > >> > >> The problem was tracked down to a very slow IOREMAP operation and > >> the excessively long ioresource lookup to insure that the user is > >> not attempting to ioremap RAM. These patches provide a speed up > >> to that function. > > > > With what result? > > > > Early measurements on our in house lab system (with far fewer cpus > and memory) shows about a 60-75% increase. They have a 31 devices, > 3000+ cpus, 10+Tb of memory. We have 20 devices, 480 cpus, ~2Tb of > memory. I expect their ioresource list to be about 5-10 times longer. > [But their system is in production so we have to wait for the next > scheduled PM interval before a live test can be done.] So you expect 1+ hours? That's still nuts. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org