From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lo.gmane.org ([80.91.229.12]) by linuxtogo.org with esmtp (Exim 4.72) (envelope-from ) id 1Qa0G8-0002aj-0z for openembedded-devel@lists.openembedded.org; Fri, 24 Jun 2011 08:52:56 +0200 Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1Qa0Cf-00058a-Oz for openembedded-devel@lists.openembedded.org; Fri, 24 Jun 2011 08:49:21 +0200 Received: from ip545070eb.adsl-surfen.hetnet.nl ([84.80.112.235]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 24 Jun 2011 08:49:21 +0200 Received: from koen by ip545070eb.adsl-surfen.hetnet.nl with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 24 Jun 2011 08:49:21 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: openembedded-devel@lists.openembedded.org From: Koen Kooi Date: Fri, 24 Jun 2011 08:49:00 +0200 Message-ID: References: <201106202316.47662.schnitzeltony@gmx.de> <201106232258.06911.schnitzeltony@gmx.de> <201106240052.59211.schnitzeltony@gmx.de> Mime-Version: 1.0 X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: ip545070eb.adsl-surfen.hetnet.nl User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.1.16) Gecko/20101127 Shredder/3.0.11pre In-Reply-To: <201106240052.59211.schnitzeltony@gmx.de> X-Enigmail-Version: 1.0.1 Subject: Re: udev 171 caching working propely? X-BeenThere: openembedded-devel@lists.openembedded.org X-Mailman-Version: 2.1.11 Precedence: list Reply-To: openembedded-devel@lists.openembedded.org List-Id: Using the OpenEmbedded metadata to build Distributions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jun 2011 06:52:56 -0000 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 24-06-11 00:52, Andreas Mueller wrote: > On Thursday, June 23, 2011 11:58:53 PM Koen Kooi wrote: >> On 23-06-11 22:58, Andreas Mueller wrote: >>> On Tuesday, June 21, 2011 11:31:45 PM Tom Rini wrote: >>>> On 06/20/2011 03:47 PM, Tom Rini wrote: >>>>> On 06/20/2011 02:16 PM, Andreas Mueller wrote: >>>>>> Dear OE-folks, >>>>>> >>>>>> Working with lastest classic oe master and angstrom it seems udev >>>>>> caching is not >>>>>> >>>>>> working as expected. On *every* boot I get: >>>>>>> Remounting root file system... >>>>>>> Caching udev devnodes >>>>>>> Populating dev cachemv: can't rename '/dev/shm/uname': No such file >>>>>>> or directory >>>>>> >>>>>> I don't know why this change came in but there was a change of storage >>>>>> location in Tom's commit few days ago [1]. To me it seems that >>>>>> >>>>>> 1. The files created by udev (init) get lost at remount so udev-cache >>>>>> (cache) is unable to find >>>>>> 2. Since this error occures not only at first boot the recipe's >>>>>> pkg_postinst_udev_append() seems never being executed. To check I >>>>>> added a simple echo 'foo text' >>>>>> in this function but 'foo text' is not found in log of first boot. >>>>>> >>>>>> Suggestions welcome >>>>> >>>>> Did udev change behaviors at some point then? I've been using an older >>>>> udev and didn't run into that problem. I changed from /tmp to /dev/shm >>>>> since we don't know that /tmp is writable at that point so we were >>>>> instead getting errors there. I wonder if we should just switch to >>>>> re-creating the contents for that step? >>>> >>>> I've gone with this change and some quick testing on a board. >>> >>> Hi Tom, >>> >>> thanks for taking care and sorry for late response - yesterday I had one >>> of these nightmares at the job... >>> >>> Now I tested the patch for two machines and sorry I am afraid to waste >>> your time again: >>> >>> First machine is overo with linux-omap-psp-2.6.32 and a hub connected to >>> the OTG connector. The kernel detects USB devices at a very early boot >>> state long before udev starts (see end of file 'overo' attached). udev >>> caching seems to work without errors. >>> >>> Second machine is tx28 with linux-2.6.38.5 (freescale imx28 based - I >>> will send patches when stable). This shows different behaviours on first >>> and all further boots (see udev-*boot attached). Problem is that after >>> second boot nothing connected to USB is detected / working. By deleting >>> /etc/udev/saved.* and rebooting all USB devices work fine and log looks >>> similar as first boot. >>> >>> Before I merged your patch I know the USB devices were working properly >>> on tx28. Don't misunderstand me: I think before your patch cache was >>> never read. Now you fixed this and it seems reading the cache does not >>> work (on my half cooked machine only?). >>> >>> I will have further investigations on this... >> >> With 171 you shouldn't need caching anymore, triggering has been sped up >> considerably, could you try disable caching and see how much it impacts >> your boot time? > Uncached feels slower. Populating all devices takes 5-10s. Is there a simple way > to create time stamps for boot messages? Another test would be to unload the kernel modules and do: killall udevd ; time ( udevadm trigger ; udevadm settle ) That takes about 1s on my beagleboard and 3.5s on my hawkboard. Systemd keeps a track of it, have a look at the bright red portions of the graphs: http://dominion.thruhere.net/koen/angstrom/systemd/beagleboardC5-ubi-201106171148.svg http://dominion.thruhere.net/koen/angstrom/systemd/hawkboard.svg I my case the caching wasn't needed, but if it starts taking >4s on 'slow' systems and >2s on 'fast' systems it is worth considering. regards, Koen -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (Darwin) iD8DBQFOBDNcMkyGM64RGpERAi2nAKCMs41YobWWtBg0SqT6RGLVeH2z0QCfTkN1 hvCaKPRpAR4HhvuHLWKRPRY= =Uy6Y -----END PGP SIGNATURE-----