Hello, In this version I added #timesRepeat: as a special selector to be inlined by the compiler (as #to:do:, #ifTrue:, ...). There was already another side effect of this addition of timesRepeat: as a special selector for XStreams. I guess we should remove it. Try to edit the default Opal options in: OpalCompiler>>#defaultOptions instead of: + optionInlineTimesRepeat put: - optionInlineTimesRepeat Then execute: OpalCompiler recompileAll. (If you run your code with a DoIt you do not need to recompileAll, but just in case ...) And see if you bug comes from the timesRepeat:. Now the bytecode for "3 timesRepeat: [ Smalltalk garbageCollect ]" is correct. But there may be some side effect in the VM I am not thinking of. 29 <20> pushConstant: 3 30 <68> popIntoTemp: 0 31 <10> pushTemp: 0 32 <76> pushConstant: 1 33 <69> popIntoTemp: 1 34 <11> pushTemp: 1 35 <10> pushTemp: 0 36 <B4> send: <= 37 <AC 09> jumpFalse: 48 39 <41> pushLit: Smalltalk 40 <D2> send: garbageCollect 41 <87> pop 42 <11> pushTemp: 1 43 <76> pushConstant: 1 44 <B0> send: + 45 <69> popIntoTemp: 1 46 <A3 F2> jumpTo: 34 48 <7C> returnTop 2013/11/25 Max Leske <maxleske@gmail.com>
I was able to isolate the image where the SegFault problem appears first: 30435. Hereâs the update method:
update30435 "self new update30435" self withUpdateLog: '11729 Sync Opa from repo: #timesRepeat optimization enabled https://pharo.fogbugz.com/f/cases/11729 11720 DateModel: Add #displayBlock: https://pharo.fogbugz.com/f/cases/11720 11727 remove unused ivar scrollBarOnLeft in ScrollPane https://pharo.fogbugz.com/f/cases/11727'. self loadTogether: self script114 merge: false. (SystemNavigation new allCallsOn: #timesRepeat:) do: [ :each | each method recompile ]. self flushCaches.
What I noticed is that 11729 is about #timesRepeat: and the code I used to trigger the SegFaults is â3 timesRepeat: [ Smalltalk garbageCollect ]â. So the problem might actually lie in #timesRepeat: rather than in #garbageCollect:
@Marcus Iâve put you into CC because I hope that you know more about #timesRepeat:
Cheers, Max
On 25.11.2013, at 08:26, Max Leske <maxleske@gmail.com> wrote:
Interesting development: no SegFaults (while using exactly the same code) when using an older Pharo image (version 30321 instead of latest). This obviously suggests that the problem lies with the image and not necessarily the vm.
Max
On 10.11.2013, at 20:10, Max Leske <maxleske@gmail.com> wrote:
On 07.11.2013, at 08:20, Max Leske <maxleske@gmail.com> wrote:
On 07.11.2013, at 00:27, vm-dev-request@lists.squeakfoundation.org wrote:
Date: Wed, 6 Nov 2013 19:23:47 -0200 From: Mariano Martinez Peck <marianopeck@gmail.com> Subject: Re: [Vm-dev] Frequent SegFaults in PharoVM with Pharo 3.0 To: Squeak Virtual Machine Development Discussion <vm-dev@lists.squeakfoundation.org> Message-ID: <CAA+-=mWDtHGQWSHx-m4u37Kj0UAMx=UG=qUCz+wMvgDT8BaQZQ@mail.gmail.com> Content-Type: text/plain; charset="windows-1252"
Max, did you try with Eliot VMs besides the pharo ones?
No, I havenât. I can try (though only on my machine), but if I canât reproduce the SegFault that doesnât mean much unfortunately. It took me 10 to 20 tries with the PharoVM tooâ¦
Iâll try anyway and let you know what I find.
Max
I just gave CogVM and NBCog a shot. Unfortunately I canât use the images because theyâve been built with PharoVM and hang after load. At least on the Pharo CI there are no jobs that create Cog / NBCog images.
So no luck with different VMs.
Max
Thanks
On Wed, Nov 6, 2013 at 6:04 PM, Max Leske <maxleske@gmail.com> wrote:
Hi
Weâve been encountering frequent SegFaults when running the Fuel tests on the Pharo CI (https://ci.inria.fr/pharo-contribution/job/Fuel/). Since today Iâve also been able to reproduce the SegFaults on my MacBook Pro (OS X 10.9) too. We have not been able to determine the cause of the SegFault but we can produce SegFaults often, although not reliable (more reliable on the CI).
The CI uses the stable VM: http://files.pharo.org/vm/pharo/linux/stable.zip I use a newer version from October on my machine: http://files.pharo.org/vm/pharo/mac/273.zip
Iâve attached all the dumps of the crashes I was able to produce on my machine, together with Appleâs crash logs.
Iâve been able to deduce the following: - garbage collection seems to be a trigger for the SegFault. When one of the methods FLMethodContextSerialization>>testFuelShouldIgnoreFuel and FLMethodContextSerialization>>testMethodContextWithNilPc contain the line â3 timesRepeat: [Smalltalk garbageCollect]â the SegFault appears nearly always (on CI). When I remove the line the builds run through. - Not all methods with the garbage collect line trigger a SegFault (I could only identify those two) - the garbage collect line itself suffices as a trigger in the mentioned methods. - The number of tests (amount of used memory?) seems to influence the appearence of the SegFault (e.g. loading "DevelopmentGroup" seems to trigger it more often than loading âBenchmarksâ) - the SegFault always appears after the tests with the garbage collect line have been run, never before - the VM canât write the crash.dmp every time
Since the SegFaults are so random I cannot give you an image to reproduce the problem. Iâve had the best results using a fresh 3.0 image ( http://files.pharo.org/image/30/30549.zip) and then evaluating the following in a workspace:
Gofer it smalltalkhubUser: 'Pharo' project: 'Fuel'; package: 'ConfigurationOfFuel'; load.
((Smalltalk at: #ConfigurationOfFuel) project version: #bleedingEdge) load: 'DevelopmentGroup'.
HDTestReport runClasses: (TestCase allSubclasses select: [ :class | class name beginsWith: 'FL']) named: âfoo'
If it doesnât work, try using the TestRunner manually. Select the default Fuel tests (alphabetically at F) and the additional Fuel tests (at the bottom of the list) and run them.
If anybody has any clue about what could be going on Iâd really appreciate any input. Iâll happily provide more information if I can.
Thanks for reading :) Max
-- Mariano http://marianopeck.wordpress.com