From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anton Blanchard Subject: Re: [PATCH 3/5]: ipr: kexec boot speed improvements Date: Wed, 27 Aug 2014 14:06:30 +1000 Message-ID: <20140827140630.1f0ee455@kryten> References: <53D6B2A4.4010102@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from ozlabs.org ([103.22.144.67]:54910 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750919AbaH0EGb (ORCPT ); Wed, 27 Aug 2014 00:06:31 -0400 In-Reply-To: <53D6B2A4.4010102@linux.vnet.ibm.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Brian King Cc: "James E.J. Bottomley" , linux-scsi , Wendy Xiong , kexec@lists.infradead.org Hi Brian, > Currently when performing a kexec boot with an ipr adapter, > the adapter gets shutdown completely, flushing all write > cache, as well as performing a full hardware reset of the card > during the shutdown phase of the old kernel. This forces > the new kernel to then wait for the adapter firmware to > reinitialize, which slows down kexec boot. There is no > need to do all of this on the newer ipr adapters, since they > support the ability to cancel outstanding error buffers. > > This patch adds a special case for kexec boot to simply > cancel these outstanding error buffers, and as long as > there is no other I/O outstanding to the adapter, which > there shouldn't be, place the adapter into a state > where it has no memory of any DMA addresses from the old > kernel, then disable the device. This significantly > speeds up kexec boot, particularly in configurations with > multiple ipr adapters. > > Signed-off-by: Brian King > --- This reduces boot time on my box from 80 seconds to 34 seconds. ppc64 kernel developers (who boot boxes continually) thank you! Tested-by: Anton Blanchard Anton