Vm-dev October 2012

vm-dev@lists.squeakfoundation.org

27 participants
45 discussions

Re: [squeak-dev] how/where is memory returned to the OS?
by Eliot Miranda 19 Oct '12

19 Oct '12

Hi Chris, On Fri, Oct 19, 2012 at 8:46 AM, Chris Muller <asqueaker(a)gmail.com> wrote: > I have an image which needed to allocate 500MB of memory for a large > operation. Now that operation is done and all objects have been > reclaimed. According to VM I am now only using 200MB. > > (Smalltalk vmParameterAt: 2) max: (Smalltalk vmParameter at: 1) > "221923374" > > However, when I look at my VM process in "top" or the System Monitor, > it still says its >500MB. > > How does this work? > Depends on the platform. On Mac OS X memory is not returned. On Windows memory is allocated and freed via VirtualAlloc and VirtualFree. On Unix memory is allocated and returned via mmap and munmap by default. What OS are you on? Looks like the unix code could be ported to the Mac easily. -- best, Eliot

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Re: [Pharo-project] Mariano's VM-building instructions don't seem to work
by Esteban Lorenzano 19 Oct '12

19 Oct '12

Hi Craig, the macosx build is not supported since a lot, as you said in your post, it relies in deprecated functions (many of them now removed). I'm maintaining the Cocoa ones (which still have some problems, but at least they use non deprecated APIs). Instead trying to build the MacOS configuration, you need to use: CogCocoaIOSConfig best, Esteban On Oct 19, 2012, at 6:40 PM, Craig Latta <craig(a)netjam.org> wrote: > > Hi all-- > > The Cog-building instructions at [1] don't seem to work: > > *** > > CMake Error at CMakeLists.txt:46 (add_executable): > Cannot find source file: > > > /Users/craig/me/behavior/spoon/processor/kernel/cog-2012-10-19/blessed/macbuild/resources/ProjectBuilder/MainMenu.nib > > *** > > Hack that one and get: > > *** > > CMake Error at HostWindowPlugin/CMakeLists.txt:17 (add_library): > Cannot find source file: > > > /Users/craig/me/behavior/spoon/processor/kernel/cog-2012-10-19/blessed/platforms/iOS/vm/iPhone/plugins/HostWindowPlugin/sqMacHostWindow.c > > *** > > Hack that one and get: > > CMake Error at CroquetPlugin/CMakeLists.txt:17 (add_library): > Cannot find source file: > > > /Users/craig/me/behavior/spoon/processor/kernel/cog-2012-10-19/blessed/platforms/Cross/plugins/CroquetPlugin/tribox.c > > *** > > There is no file called “tribox.c”. Now what? > > > thanks! > > -C > > [1] > http://marianopeck.wordpress.com/2011/04/10/building-the-vm-from-scratch-us… > > -- > Craig Latta > www.netjam.org/resume > +31 6 2757 7177 > + 1 415 287 3547 (no SMS) > >

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[OT] Lars Bak on VM's
by Torsten Bergmann 19 Oct '12

19 Oct '12

Lars Bak presents several language virtual machines (Self, Strongtalk, Hotspot), why they matter and how they influenced V8 and Dart. http://www.infoq.com/presentations/Performance-V8-Dart

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Re: Multiple Bytecode Sets
by Eliot Miranda 16 Oct '12

16 Oct '12

Hi Stefan, On Tue, Oct 16, 2012 at 12:11 PM, Stefan Marr <Stefan.Marr(a)vub.ac.be> wrote: > Hi Eliot: > > May I ask you to give me a brief, high-level description of how the > support for multiple bytecode sets works? > sure. > Do you switch between different dispatch tables based on the method flag? > Or do you extend the existing one and include the bit into the dispatch? > This scheme is suggested by Claus Gittinger, and he uses something very similar in Smalltalk/X. The idea is merely to include an offset that selects the bytecode set in the dispatch and set this offset on every send and return. So with two bytecode sets there are 512 cases in the interpreter's dispatch loop and the offset is either 0 or 256. In the Squeak VM this means code such as StackInterpreter methods fetchNextBytecode "This method fetches the next instruction (bytecode)." currentBytecode := self fetchByte + bytecodeSetSelector setMethod: aMethodObj "Set the method and determine the bytecode set based on the method header's sign." <inline: true> method := aMethodObj. self assert: (objectMemory isOopCompiledMethod: method). bytecodeSetSelector := (self methodUsesAlternateBytecodeSet: method) ifTrue: [256] ifFalse: [0] methodUsesAlternateBytecodeSet: aMethodObj <api> <inline: true> "A negative header selects the alternate bytecode set." ^self headerIndicatesAlternateBytecodeSet: (self headerOf: aMethodObj) headerIndicatesAlternateBytecodeSet: methodHeader "A negative header selects the alternate bytecode set." ^(objectMemory integerValueOf: methodHeader) < 0 Do you have any performance numbers, or pointers to literature? > I couldn't see much of an impact when I measured it, but I don't have my measurements handy. Modern processors cache the read so well that even in the interpreter impact is minimal (it was certainly less than 10%, probably less than 5%, in a pure interpreter), and of course in the JIT it matters not at all. But the impact was enough that I ended up conditionalizing the code so it reads fetchNextBytecode "This method fetches the next instruction (bytecode). Each bytecode method is responsible for fetching the next bytecode, preferably as early as possible to allow the memory system time to process the request before the next dispatch." self cppIf: MULTIPLEBYTECODESETS ifTrue: [currentBytecode := self fetchByte + bytecodeSetSelector] ifFalse: [currentBytecode := self fetchByte] That was easier than trying to define bytecodeSetSelector as 0, e.g. via a macro. I found hints to Smalltalk/X, VisualAgeJava/Smalltalk, and I think > MagLev/Gemstone might also use that kind of technique. > But, unfortunately, Google is a bit shy about papers, or interesting > references. > I don't suppose its something people do a lot. Claus' VM is the only one I was aware of. I think its useful to support multiple languages and to support migrating the bytecode set using incremental development, but in a production VM if one didn't need the support I think one would end up disabling it. Thanks a lot > Stefan > -- cheers, Eliot

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Multiple Bytecode Sets
by Stefan Marr 16 Oct '12

16 Oct '12

Hi Eliot: May I ask you to give me a brief, high-level description of how the support for multiple bytecode sets works? Do you switch between different dispatch tables based on the method flag? Or do you extend the existing one and include the bit into the dispatch? Do you have any performance numbers, or pointers to literature? I found hints to Smalltalk/X, VisualAgeJava/Smalltalk, and I think MagLev/Gemstone might also use that kind of technique. But, unfortunately, Google is a bit shy about papers, or interesting references. Thanks a lot Stefan -- Stefan Marr Software Languages Lab Vrije Universiteit Brussel Pleinlaan 2 / B-1050 Brussels / Belgium http://soft.vub.ac.be/~smarr Phone: +32 2 629 2974 Fax: +32 2 629 3525

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X11 display problems
by Bert Freudenberg 15 Oct '12

15 Oct '12

Hi Ian, folks, we just got another report of the two display problems in X11: http://tracker.squeakland.org/browse/SQ-1126 One issue is the window shrinking to a vertical line, the other not updating the whole window after maximizing. Apparently removing -xshm helps for the shrinking problem. If anyone has any insight on these that would be great! - Bert -

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Fwd: [Pharo-users] Pharo sound capabilites. What options?
by Igor Stasenko 13 Oct '12

13 Oct '12

can anyone give an answer? i never used sound stuff, don't really knows what exists in VMs. like, is Sound plugin just for playing samples (which already decompressed etc) or there can be some higher level API to that, so you can play ogg streams etc. ---------- Forwarded message ---------- From: Volkert Barr <volkert(a)nivoba.de> Date: 12 October 2012 19:47 Subject: [Pharo-users] Pharo sound capabilites. What options? To: pharo-users(a)lists.gforge.inria.fr Dear all, I am want to write in game in pharo 1.4, but need sound capabilities (playing mp3/ogg or midi, ..). what are my options here? BW, Volkert -- Best regards, Igor Stasenko.

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HackerNews + vm-dev = a lightbulb saying "STACK!"
by Chris Cunnington 11 Oct '12

11 Oct '12

I saw an interesting post on HackerNews [1] about a book called "Stack Computers: The New Wave" (1989)[2]. I thought, that's pretty interesting. Stack computers. Stack languages. Forth. Hmmm, Forth. I wonder if it would be worth spending some time on Forth? Then there's a post on GreenArrays, Inc. [3] and Chuck Moore and ColorForth [4] and such. And I think, Yea. That's cool. But I shouldn't really go down this road. How are stack languages related to Smalltalk? And then I realized the StackVM is called a StackVM because it uses a ... STACK. Oh, right. Stack. Maybe the informing principle of the StackVM is that it uses a stack. Like Forth. Sometimes a brick has to fall on my head before I see what's going on. Chris [1] http://news.ycombinator.com/ [2] http://www.ece.cmu.edu/~koopman/stack_computers/index.html [3] http://www.greenarraychips.com/ [4] http://www.colorforth.com/

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some issues with latest standard VM
by Chris Muller 09 Oct '12

09 Oct '12

I can't seem to interrogate the squeak VM version from the command-line with the 4.10.2.2614 Unix VM. $ squeak -version cannot find VM to run image 'squeak' with option '' When I start an image, I see what appear to be a couple of debugging messages in the console: $ squeak myImage & $ CHECKING cogvm CHECKING squeakvm Finally, I've discovered after doing heavy work in an image in Cog -- something maybe happens to it because, while I can still open it under Cog, I can't open it with the regular VM. $ squeak myImage & $ CHECKING cogvm CHECKING squeakvm squeakvm: /home/piumarta/squeak/platforms/unix/vm/sqUnixMemory.c:177: uxGrowMemoryBy: Assertion `newDelta >= 0' failed. This last error also occurs with the 2357 VM, so it's been around a while. With a fresh image saving under Cog and opening under the 2614 VM works fine -- it's only after having done a lot of work in the image that something happens to make the standard VM crash when trying to open it, even though it still opens fine under Cog 2585.

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HackerNews + vm-dev = a lightbulb saying "STACK!"
by Chris Cunnington 07 Oct '12

07 Oct '12

> One of most modern ones, i think: > http://factorcode.org/ <http://factorcode.org/> Cool. Thanks for recommending this. I looked for a Forth for Mac and saw this, which looked better, but was wondering if it was any good. Chris

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Vm-dev October 2012