From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by yocto-www.yoctoproject.org (Postfix, from userid 118) id C9A82E011C1; Fri, 13 Jul 2018 09:23:48 -0700 (PDT) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on yocto-www.yoctoproject.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 X-Spam-HAM-Report: * -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low * trust * [62.142.5.116 listed in list.dnswl.org] * -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] X-Greylist: delayed 326 seconds by postgrey-1.32 at yocto-www; Fri, 13 Jul 2018 09:23:46 PDT Received: from emh06.mail.saunalahti.fi (emh06.mail.saunalahti.fi [62.142.5.116]) by yocto-www.yoctoproject.org (Postfix) with ESMTP id E075AE00E85 for ; Fri, 13 Jul 2018 09:23:46 -0700 (PDT) Received: from uwe1 (unknown [193.65.204.41]) by emh06.mail.saunalahti.fi (Postfix) with ESMTP id 999BD3016F; Fri, 13 Jul 2018 19:18:17 +0300 (EEST) From: Uwe Geuder To: yocto@yoctoproject.org Date: Fri, 13 Jul 2018 19:18:17 +0300 Message-ID: <87va9jw1me.fsf@snkmail.com> MIME-Version: 1.0 Subject: Why can diffsigs take sometimes really looooong? X-BeenThere: yocto@yoctoproject.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Discussion of all things Yocto Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 13 Jul 2018 16:23:48 -0000 Content-Type: text/plain Hi! At times I find the diffsigs command useful/educational to understand what is going on in my build. $ bitbake-diffsigs -t myimage do_image Often the result is shown in no time. However, recently I got some cases were it takes 150 (!) minutes to show a simple difference (1 line changed in do_install of systemd). In comparision building after that change (with sstate) takes some 10 minutes. And building everything from scratch (no sstate) takes just a bit over 50 minutes on the same machine. Of course the build can make good use of my 8 cores / 16 threads, whereas diffsigs seems to run in only 1 core. Still, shouldn't every build calculate all the dependencies, so running diffsigs should only be a small fraction of that work? Is there a natural explanation why diffsigs can sometimes be so slow? Just curious to understand what is going on there. I am on Rocko 2.4.3 if that makes a difference. Regards, Uwe Geuder Neuro Event Labs Oy Tampere, Finland uwe.gexder@neuroeventlabs.com (Bot check: fix one obvious typo)