From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail5.wrs.com (mail5.windriver.com [192.103.53.11]) by mail.openembedded.org (Postfix) with ESMTP id 21F68607A5 for ; Wed, 7 Sep 2016 14:15:20 +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 u87EFJQn006251 (version=TLSv1 cipher=AES128-SHA bits=128 verify=OK); Wed, 7 Sep 2016 07:15:19 -0700 Received: from server.local (147.11.117.229) by ALA-HCA.corp.ad.wrs.com (147.11.189.40) with Microsoft SMTP Server id 14.3.248.2; Wed, 7 Sep 2016 07:15:18 -0700 To: Markus Lehtonen , Richard Purdie , openembedded-core References: <1473240442.20226.111.camel@linuxfoundation.org> <86d45370-2472-5be2-d1c9-b0e44bd53291@windriver.com> <1473251611.10544.9.camel@linux.intel.com> <9bbebe09-5e7b-0125-460e-54c5ecb4c95a@windriver.com> <1473256835.10544.18.camel@linux.intel.com> From: Bruce Ashfield Message-ID: <8fa069ee-7141-ae85-5b91-94885d4205f1@windriver.com> Date: Wed, 7 Sep 2016 10:15:17 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <1473256835.10544.18.camel@linux.intel.com> Subject: Re: Speed regression in the 4.8 kernel? 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: Wed, 07 Sep 2016 14:15:21 -0000 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit On 2016-09-07 10:00 AM, Markus Lehtonen wrote: > On Wed, 2016-09-07 at 08:44 -0400, Bruce Ashfield wrote: >> On 2016-09-07 8:33 AM, Markus Lehtonen wrote: >>> On Wed, 2016-09-07 at 07:56 -0400, Bruce Ashfield wrote: >>>> On 2016-09-07 5:27 AM, Richard Purdie wrote: >>>>> Hi Bruce, >>>>> >>>>> I deliberately spaced out the merges of various things so we could >>>>> get >>>>> performance measurements of the system as it happened. >>>>> Unfortunately >>>>> the 4.8 kernel appears to regress the kernel build time quite >>>>> significantly: >>>>> >>>>> The raw data: >>>>> >>>>> ypperf02,master:9428b19a7dd1d265d9f3211004391abe33ea0224,uninative >>>>> -1.3 >>>>> -414 >>>>> -g9428b19,1:01:32,4:21.16,1:00:32,2:10.86,0:16.19,0:11.21,0:01.20,5 >>>>> :34. >>>>> 73,26701616,6445160,1477762,5446116 >>>>> ypperf02,master:9428b19a7dd1d265d9f3211004391abe33ea0224,uninative >>>>> -1.3 >>>>> -414 >>>>> -g9428b19,1:04:14,4:23.82,1:00:40,2:13.70,0:16.18,0:11.28,0:01.22,5 >>>>> :45. >>>>> 48,26697516,6445724,1478048,5446490 >>>>> ypperf02,master:b9d90ace005597ba35b59adcd8106a1c52e40c1a,uninative >>>>> -1.3 >>>>> -438 >>>>> -gb9d90ac,1:03:16,7:22.13,1:02:46,2:16.60,0:16.32,0:11.04,0:01.21,5 >>>>> :42. >>>>> 11,30852876,10550952,1707255,5912282 >>>>> ypperf02,master:f7ca989ddc6d470429b547647d3fbaad83a982d9,uninative >>>>> -1.3 >>>>> -446 >>>>> -gf7ca989,1:04:42,7:29.05,1:03:04,2:19.71,0:16.21,0:11.05,0:01.24,5 >>>>> :52. >>>>> 83,30845748,10551316,1707615,5912122 >>>>> >>>>> which shows the time for "bitbake virtual/kernel -c cleansstate; >>>>> time >>>>> bitbake virtual/kernel" goes from 4:20 to 7:22. The disk footprint >>>>> of >>>>> the build went from 26GB to 30GB. The build with rm_work size went >>>>> from >>>>> 6.4GB to 10.5GB. The overall build time went up 2-3 minutes which >>>>> looks >>>>> like the increased kernel build time. The increased time may well >>>>> be >>>>> from the increased data being generated/processed. >>>> >>>> Is it the actual compile itself ? What's the trick to actually get >>>> individual task >>>> >>>> For the disk footprint, I can check the refs in the tree and purge >>>> anything that may be dangling. That being said, I can't do that to >>>> the repository on the git server, so we may need someone that can >>>> issue a git gc directly on the repository. >>>> >>>>> >>>>> We can't ship M3 with this much of a performance degradation and >>>>> increased space usage :(. Any idea what changed? >>>> >>>> Nope. I can only focus on one thing at a time. I was worried about >>>> a functionally correct kernel (which I still am) and haven't looked >>>> at anything in the peripheral yet. >>>> >>>> If I can get individual task timings, I can look at it more. >>>> >>>> I'm seeing significantly faster meta data phases, etc, so I'm >>>> interested >>>> to know if this is purely in the build steps. >>> >>> In my own test setup I'm seeing similar increase in kernel build time. >>> >>> Comparing the buildstats of kernel builds from before and after the 4.8 >>> I >>> got the following numbers (these are cpu times consumed by the tasks >>> >>> TASK ABSDIFF RELDIFF CPUTIME1 CPUTIME2 >>> do_package +17.5s +133.1% 13.1s -> 30.6s >>> do_deploy +19.9s +1449.4% 1.4s -> 21.3s >>> do_package_write_rpm +86.8s +714.7% 12.1s -> 98.9s >>> do_compile_kernelmodules +139.4s +35.9% 388.2s -> 527.6s >>> do_compile +201.1s +30.0% 670.3s -> 871.4s >> >> ok. So as long as the significant increases aren't in do_kernel_metadata >> or do_patch (those two I've measured), we are dealing with something >> in the kernel build itself. I can deal with the footprint by inspecting >> the repo, but Kbuild is a tougher nut to crack. > > I took a look at the kernel build directory size and there was a huge > difference (500M vs. 3.5G). Seeing that significant change I took a look at > the kconfigs and found out that CONFIG_DEBUG_KERNEL and CONFIG_DEBUG_INFO > are enabled, among other things. Looking at the kernel metadata I can see > that these are enabled in ktypes/base/base.cfg. > > I guess this is not intended? Sure enough, there's a missing series in the 4.8 and master branches of the kernel meta repo. I'm going to do a full audit and will send meta data updates once I've ensured nothing else is missing. Bruce > > Thanks, > Markus > > >> Out of curiosity, is the 4.4 kernel on master showing a significantly >> shorter build time ? I'm assuming the before is the 4.4 kernel .. but >> I just wanted to be sure, so we can rule out something else that might >> be pathologically reacting to the sheer amount of I/O in a kernel build. >> >> Bruce >> >>> >>> >>> I haven't tried to analyze what is causing this yet, though. >>> >>> >>> Thanks, >>> Markus >>> >> >