From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail5.wrs.com (unknown [64.129.254.146]) by mail.openembedded.org (Postfix) with ESMTP id 327D26013D for ; Mon, 26 Oct 2015 21:35:40 +0000 (UTC) Received: from ALA-HCA.corp.ad.wrs.com (ala-hca.corp.ad.wrs.com [147.11.189.40]) by mail5.wrs.com (8.15.2/8.15.2) with ESMTPS id t9QLZeHl029835 (version=TLSv1 cipher=AES128-SHA bits=128 verify=OK); Mon, 26 Oct 2015 14:35:40 -0700 Received: from Marks-MacBook-Pro.local (172.25.36.227) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server id 14.3.248.2; Mon, 26 Oct 2015 14:35:39 -0700 To: Phil Blundell References: <562E3896.6080405@windriver.com> <1445875841.5251.107.camel@pbcl.net> <562E58BE.9060003@windriver.com> <1445878220.5251.110.camel@pbcl.net> <562E5AF1.3080807@windriver.com> <1445894299.6900.8.camel@pbcl.net> From: Mark Hatle Organization: Wind River Systems Message-ID: <562E9CAA.7000805@windriver.com> Date: Mon, 26 Oct 2015 16:35:38 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <1445894299.6900.8.camel@pbcl.net> Cc: Patches and discussions about the oe-core layer Subject: Re: Prelink problems -- need help! X-BeenThere: openembedded-core@lists.openembedded.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Patches and discussions about the oe-core layer List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Oct 2015 21:35:42 -0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit On 10/26/15 4:18 PM, Phil Blundell wrote: > On Mon, 2015-10-26 at 11:55 -0500, Mark Hatle wrote: >> -last- time I got concrete numbers on a complex boot process. It was on the >> order of 1-5% boot time.. and a fairly large number of pages saved.. (which >> reduced fragmentation as well as saved memory.) > > I'm slightly surprised at the 5% figure. Martin Jansa posted some > statistics in another thread earlier today which showed an improvement > from prelink of just under 0.5% (0.24 seconds saved out of 49.51 seconds > total) and that's more like what I would have expected. What sort of > binaries were you running on the system you measured? At the time, it was systemd, X11, a custom control module and a custom UI program. The custom UI program was written in C++ and had a heck of a lot of libraries attached, and lots of RPC via dbus. > I also don't entirely understand the fragmentation argument. We're not > talking about a no-mmu configuration here, are we? Fragmentation takes time and can slow down memory allocation. We've got both the kernel page allocation, as well as the internal glibc memory allocation. They work together, but are not the same. (glibc will grab pages of memory from the kernel and then dish them out. As this memory fragments, it has to pull more from the kernel to compensate... as well as free blocks to get more contiguous memory allocated).. It's a bit of a viscous cycle of some small systems. --Mark > p. > >