Date: Wed, 27 Jun 2018 19:24:57 -0700 From: bob prohaska <fbsd@www.zefox.net> To: Mark Millard <marklmi@yahoo.com> Cc: freebsd-arm@freebsd.org, bob prohaska <fbsd@www.zefox.net> Subject: Re: RPI3 swap experiments Message-ID: <20180628022457.GA30110@www.zefox.net> In-Reply-To: <C6303FC5-B412-472C-98E4-9A1E45C38535@yahoo.com> References: <201806261040.w5QAeBKq035183@donotpassgo.dyslexicfish.net> <A6986B21-FF6E-48F5-9F3A-06B3D2A92C55@yahoo.com> <20180626151843.GD17293@www.zefox.net> <3525D7C7-F848-45A1-BD85-2DAC895DF48C@yahoo.com> <20180626222834.GA20270@www.zefox.net> <28012DFB-37A0-461A-BB62-CD3EE61E82F0@yahoo.com> <20180627054027.GA22144@www.zefox.net> <CC72E766-03CB-476C-8F2B-DAAC266CE63D@yahoo.com> <20180627194217.GA27793@www.zefox.net> <C6303FC5-B412-472C-98E4-9A1E45C38535@yahoo.com>
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On Wed, Jun 27, 2018 at 06:12:53PM -0700, Mark Millard wrote: > On 2018-Jun-27, at 12:42 PM, bob prohaska <fbsd at www.zefox.net> wrote: > > > On Tue, Jun 26, 2018 at 11:30:52PM -0700, Mark Millard wrote: > >> On 2018-Jun-26, at 10:40 PM, bob prohaska <fbsd at www.zefox.net> wrote: > >> > >> . . . > >> For (A), have you tried any examples of: > >> > >> sufficient swap on mmcsd0 (or other such) with no swap > >> on da0 (but /usr and /var on /dev/da0)? > > Yes, that is the configuration which completes successfully. > >> > >> If yes, did you check on if there were /dev/da0 errors > >> logged? What, if any, /dev/da0 errors where logged? > >> None? > > Correct, no errors on da0 when -j4 buildworld is successful. > > Good to know. Thanks. > > >> For (B), have you tried any examples of: > >> > >> insufficient swap on (say) mmcsd0 and no use of the > >> /dev/da0 drive that has reported errors at all, > >> /usr/ and /var not on mmcsd0 (or whatever was used > >> for swap) either? Did some drive end up reporting > >> errors? Which? Did the system still crash as well? > >> > > I think this is the standard test case: > > /usr and /var on /dev/da0 > > /tmp on /dev/mmcsd0s3a > > swap on /dev/mmcsd0s3b > > > > This configuration has crashed reliably with errors on /dev/da0 but no other "disk" errors. > > Did I understand the question correctly? > > I intended for "no use of /dev/da0" to indicate > that not even /usr or /var were from the device > that has been logging the errors. For example: > having /usr or /var on the mechanical disk and > the known-problem disk not connected at all. > Not yet, but absent new developments I'm running out of other things to try. My hesitations stems partly from my own sloth, but mostly from a concern that I'll introduce confounding changes unintentionally. I'm hopeful Jaimie will get his Pi3 running and see something interesting. Some time ago I asked whether it would be better to dd the existing da0 onto another device or better to construct a complete new installation (new snapshot on a new microSD plus a new USB thumb drive). Would you venture a guess? > This would get either no-errors or some other > device would get errors, possibly the mechanical > disk (if that was the type used for a test). > > >> > >> > >> Have such test-context combinations been tried? > >> > >> Without any logs to look at for such alternatives, I > >> can not try to compare/contrast such to the others > >> examples. > >> > > > > Understood. The matrix of test conditions is not completely filled, > > and the test of different media for /dev/da0 has not yet been made. > > I'd like to play with stress2 and ports/sysutils/stress before doing > > that. > > It would be handy for something simpler than buildworld to be > able to induce some of the types of problems, for sure. > It's difficult to gather persuasive test statistics at one trial per day 8-) > > There is a new, successful -j4 buildworld swapuse.log for the case > > of 3 GB of USB flash swap at > > > > http://www.zefox.net/~fbsd/rpi3/swaptests/r335576/3gbusbflash/ > > > > I do not see a console.log or notes about the console messages > (or lack of such). Where there any messages there of note? No > device errors? Was such checked for? > Nothing on the console apart from normal remote-login failures. The gstat data shows widely-scattered large delays, but they're brief and don't seem to cause trouble. > > The system is now up to r335655 and I'm trying to replicate > > earlier crash behavior before proceeding further. > > > > Sounds good. > > I will note that the following might help memory handling > for your context (small memory context): > > Author: alc > Date: Tue Jun 26 18:29:56 2018 > New Revision: 335674 > URL: https://svnweb.freebsd.org/changeset/base/335674 > > Log: > Update the physical page selection strategy used by vm_page_import() so > that it does not cause rapid fragmentation of the free physical memory. > > Reviewed by: jeff, markj (an earlier version) > Differential Revision: https://reviews.freebsd.org/D15976 > It's encouraging that folks are making some progress. Thanks for reading! bob prohaska
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