Vm-dev July 2008

vm-dev@lists.squeakfoundation.org

14 participants
14 discussions

Profiling and delay accuracy
by Andreas Raab 06 Aug '11

06 Aug '11

Hi Folks - For a long time now I had this feeling that MessageTally reports pretty bogus results in many situations without being able to precisely track down why this would be the case. Today I was looking at primitiveResponse() and, much to my surprise, noticed that the checkForInterrupts() that used to be there for years is gone (see Squeak3.6 for example which still has it). The sole reason for this check was to get both high delay accuracy and good profiling behavior. Consider this example: fc := FormCanvas on: Display. MessageTally spyOn:[ 1 to: 100 do:[:i| fc fillColor: Color white. fc printString. ]. ]. Using 3.6 this will be measured correctly as: **Tree** 87.5% {243ms} FormCanvas>>fillColor: |87.5% {243ms} GrafPort>>fillRect:offset: | 87.5% {243ms} GrafPort>>copyBits 12.5% {35ms} FormCanvas(Object)>>printString 12.5% {35ms} FormCanvas(Object)>>printStringLimitedTo: whereas the 3.10 reports it as **Tree** 99.6% {670ms} FormCanvas(Object)>>printString 94.9% {639ms} primitives 4.6% {31ms} FormCanvas(Object)>>printStringLimitedTo: I think you can see the problem and just imagine what this does to any cumulative results. I also wonder what that change does to platforms that don't have high-resolution asynchronous timers. This used to be the one place where we would catch timer changes at high resolution and unless the platform forces high resolution timer interrupts asynchronously (by resetting the interrupt counter) we must be loosing a lot in terms of delay accuracy. (it just so happens that the Windows VM *does* do asynchronous timer interrupts so I never noticed this but I'm very curious about the difference on Linux which typically still has pretty bad timer granularity). Any opinions? My feeling is that the timer check should go back in for all of the above reasons. At the very least a quickCheckForInterrupt() is required but I actually think putting the full check back in is worth it. Cheers, - Andreas

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Joys of Squeak-dev image, VM Compiling on MacIntel and Spoon remote OtherBrowsing
by Ken G. Brown 16 Nov '10

16 Nov '10

MacPro OS X 10.4.9 Xcode 2.4.1 Squeak-dev-114-2, VMMaker 2.8b6.1, Squeak 3.8.15beta6U.app, and version 1657 of svn MacOS VM sources, and Spoon v2a12. Downloaded http://www.squeakvm.org/cgi-bin/viewcvs.cgi/ trunk version 1657 for MacOS Ran squeak-dev-beta-114-2.image on Squeak 3.8.15beta6U.app Loaded VMMaker 3.8b6.1 from dev image Universes. Generated vm sources by following instructions in <http://www.squeakvm.org/cgi-bin/viewcvs.cgi/trunk/platforms/Mac%20OS/vm/Doc…> Fought with Xcode wanting to use MacOSX10.3.9.sdk for ppc which was giving an error which was known and documented in the Readme. Finally figured out what Xcode wanted so built universal app just using 10.4.9 sdk. Couple issues: Exupery references remain in sqnamedPrims.h and sqPlatformSpecific.h from svn version 1657, I just commented them out. Notes said: Info-NPSqueak__Upgraded_.plist was to be found in the Developer directory. I could not find it so scammed a info.plist out of John's Squeak 3.8.15beta6U.app vm. Not sure what impact this has. And much, much diddling about figuring out various things... Finally got a build. It's a lot smaller (3.9MB) than John McIntosh's Squeak 3.8.15beta6U.app (8.1MB), and it looks like it is a PowerPC one but at least it runs. I'll look into the Xcode build process some more. Then: Replaced interp.c with Craig's interp.c for Spoon, rebuilt and got a VM with Spoon client stuff. Downloaded Spoon release 2a12. Moved a copy of Flow plugin from within Craig's naiad.app package into a plugins subdirectory where the new spoon client compatible MacIntel universal VM was run from. Followed Craig's Spoon instructions for loading niaid.st and niaid.pr into the 3.10 image (Squeak-dev-114-2) running on the new VM. Did the run spoon.app thing from Spoon.dmg (version 2a12), needs to be done twice if Safari is not running. Got Spoon processor running. Followed instructions again in the Spoon client and lo! Got OtherBrowser browsing the Spoon memory running on processor. Yay Craig! Who do i get to sign my certificate? :) Ken

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How to use Croquet VMMaker
by Matthew Fulmer 29 Apr '09

29 Apr '09

Hi. In anticipation of working on HydraVM, I am trying to test as close a configuration as possible to HydraVM without being hydra. That is, load the nearest ancestor VMMaker and C sources to hydra, and try to make a working VM. This should help ensure that there are no "normal" bugs once I switch to Hydra, only hydra bugs. So, I did that: Here is my setup: - Fedora core 7 on x86 processor - Release 3.9 image/VM from squeak.org - Load FFI from SqueakMap - Load VMMaker-ar.70 from http://jabberwocky.croquetproject.org:8889/Homebase/ - Checkout http://squeakvm.org/svn/squeak/trunk revision 1796 (The nearest ancestor of HydraVM) I pointed VMMaker at the platforms directory in the checkout, and told it to build source in platforms/unix/src. I selected all plugins to be external, but moved FilePlugin and SocketPlugin to be internal. Then I did mkdir unixbuild cd unixbuild ../platforms/unix/config/configure make make fails linking gnu-interp.o: /bin/sh /home/matthewf/squeak/vm/hydravm-trunk-base/unixbuild/libtool --mode=link gcc -g -O2 -fomit-frame-pointer -DLSB_FIRST=1 -export-dynamic -R/usr/local/lib -o squeak vm/vm.a FilePlugin/FilePlugin.a SocketPlugin/SocketPlugin.a disabledPlugins.o version.o -lutil -ldl -lm -lnsl vm/vm.a gcc -g -O2 -fomit-frame-pointer -DLSB_FIRST=1 -o squeak disabledPlugins.o version.o -Wl,--export-dynamic vm/vm.a FilePlugin/FilePlugin.a SocketPlugin/SocketPlugin.a -lutil -ldl -lm -lnsl vm/vm.a -Wl,--rpath -Wl,/usr/local/lib vm/vm.a(gnu-interp.o): In function `primitiveGetWindowLabel': /home/matthewf/squeak/vm/hydravm-trunk-base/unixbuild/vm/gnu-interp.c:15141: undefined reference to `ioGetWindowLabel' vm/vm.a(gnu-interp.o): In function `primitiveSetWindowLabel': /home/matthewf/squeak/vm/hydravm-trunk-base/unixbuild/vm/gnu-interp.c:18770: undefined reference to `ioSetWindowLabelOfSize' collect2: ld returned 1 exit status Building this VM worked when using the latest VMMaker from SqueakMap (VMMaker-tpr.58), everything else the same. Is there something else I need to do in order to build using the Croquet VMMaker? I want to use it specifically, since the Hydra VMMaker is derived from it. The dev notes on Hydra are at http://squeakvm.org/~sig/hydravm/devnotes.html -- Matthew Fulmer -- http://mtfulmer.wordpress.com/ Help improve Squeak Documentation: http://wiki.squeak.org/squeak/808

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Interpreter>>signed32BitValueOf: and signed64BitValueOf: broken
by Andreas Raab 26 Nov '08

26 Nov '08

Hi - I just noticed hat Interpreter>>signed32BitValueOf: and signed64BitValueOf: are broken for edge cases. The following example will illustrate the problem: array := IntegerArray new: 1. array at: 1 put: 16rFFFFFFFF. "should fail but doesn't" array at: 1. "answers -1 incorrectly" array := IntegerArray new: 1. array at: 1 put: -16rFFFFFFFF. "should fail but doesn't" array at: 1. "answers 1 incorrectly" The problem is that both signed32BitValueOf: as well as signed64BitValueOf: do not test whether the high bit of the magnitude is set (which it mustn't to fit into a signed integer). The fix is trivial in both cases - basically all that's needed at the end of both functions is this: "Filter out values out of range for the signed interpretation such as 16rFFFFFFFF (positive w/ bit 32 set) and -16rFFFFFFFF (negative w/ bit 32 set). Since the sign is implicit in the class we require that the high bit of the magnitude is not set which is a simple test here" value < 0 ifTrue:[^self primitiveFail]. negative ifTrue:[^0 - value] ifFalse:[^value] Cheers, - Andreas

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2nd CfP (new submission deadline) for VMIL
by Michael Haupt 31 Jul '08

31 Jul '08

** apologies for multiple copies ** ** update: submission deadline moved to August 15 ** Second international workshop on Virtual Machines and Intermediate Languages for emerging modularization mechanisms (VMIL 2008) - a one-day workshop affiliated with OOPSLA 2008. http://www.cs.iastate.edu/~design/vmil/ Submission URL: http://www.easychair.org/conferences/?conf=VMIL-08 Important Dates Submission Deadline: Aug 15, 2008, 23:59 Samoan Notification of Acceptance: Sept 4, 2008 Camera ready copy due: Oct 1, 2008 Workshop: Oct 19, 2008 Program Committee * Eric Bodden (McGill University, Canada) * Juan Chen (Microsoft Research, USA) * Shigeru Chiba (Tokyo Institute of Technology, Japan) * Sophia Drossopoulou (Imperial College, UK) * Eric Eide (University of Utah, USA) * Matthew Flatt (University of Utah, USA) * Gregor Kiczales (University of British Columbia, Canada) * Hidehiko Masuhara (University of Tokyo, Japan) * Greg Morrisett (Harvard University, USA) * Angela Nicoara (ETH Zurich, Switzerland) * Harold Ossher (IBM Research, USA) * and the organizers Organizers * Hridesh Rajan, (Iowa State University, USA) * Christoph Bockisch, (Darmstadt University of Technology) * Michael Haupt (Hasso Plattner Institute, University of Potsdam, Germany) * Robert Dyer (Iowa State University, USA) Motivation and Objectives Modern programming languages are compiled to intermediate code preserving the intention of high-level language constructs. Emerging modularization mechanisms, however, lack such handling. Recent research results have shown that deeper support for these modularization mechanisms, e.g., in virtual machines and intermediate languages, is feasible; it allows applying tailored optimizations and radically improves development processes such as incremental compilation, debugging, etc. The VMIL workshop, second in the series, is a forum for research in virtual machines and intermediate languages with support for emerging modularization mechanisms such as mix-ins, units, open classes, hyper-slices, adaptive methods, roles, composition filters, layers, pointcuts-and-advice, and inter-type declarations. Topics of interest include, but are not limited to: compilation-based and interpreter-based virtual machines as well as intermediate language designs with dedicated support for emerging modularization mechanisms, compilation techniques, optimization strategies, improved techniques for fast predicate evaluation (e.g., of pointcuts) inside virtual machines, and advanced caching and memory management schemes. The areas of interest include, but are not limited to: compilation-based and interpreter-based virtual machine as well as intermediate language designs that better support these emerging modularization mechanisms, intermediate language constructs that better support these modularization mechanisms, compilation techniques from high-level languages to enhanced intermediate languages, optimization strategies for reduction of runtime overhead due to either compilation or interpretation, improved techniques for fast evaluation of pointcuts and other predicates inside virtual machines, use cases for deeper support in the virtual machines and intermediate languages, advanced caching and memory management schemes in support of the mechanisms. Paper Categories In these key areas, we invite high-quality papers in the following two categories. * Research and experience papers: These submissions should describe work that advances the current state of the art in support of advanced separation of concerns techniques in virtual machines and intermediate languages. Experience papers that are of broader interest and describe insights gained from practical applications. The page limit for these submissions is 10 pages. * Position papers: These submissions present and defend the author/s position on a topic related to the broader area of the workshop. The page limit for these submissions is 6 pages. Review Process The program committee will evaluate each paper based on its relevance, significance, clarity and originality. Each submission will be reviewed by at least three PC members. Paper Submission Papers should be submitted in PDF format at the submission URL http://www.easychair.org/conferences/?conf=VMIL-08. The results described must be unpublished and must not be under review for another workshop, conference or journal. Submissions must conform to ACM SIGPLAN format and must not exceed the page limit of the category in which it is classified by authors (including all text, figures, references and appendices). Submissions which do not conform to this will be desk rejected without reviews.

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Potato blog
by Michael Haupt 28 Jul '08

28 Jul '08

Dear all, just to let you know, maybe someone is interested... we've started a blog accompanying the Potato project (i.e., the JSqueak offspring): http://potatovm.blogspot.com/ There's not too much there yet, but hey, we've only just begun. :-) Best, Michael

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A gprof listing of memory access functions in the interpreter
by David T. Lewis 21 Jul '08

21 Jul '08

I don't know if this is of any general interest, but attached is a gprof output listing of a Squeak VM with the memory access routines from sqMemoryAccess.h recoded in Slang. I now have the Slang inlining working so that it can fully inline all of these methods. With the Slang inlining activiated, performance is essentially identical to that of the normal macros in sqMemoryAccess.h. By turning the Slang inlining off, the functions are all called individually, which is what I used to generated the attached profile. The host is 64-bit Linux AMD. The profile was run by opening a largish image, running "0 tinyBenchmarks" a half dozen times, and exiting the image without saving. So far, the advantages of putting the memory access routines into the image as Slang seem to be: - You can step into the methods in a debugger - The methods can be profiled - Exposes type declaration problems previously hidden by the macros Is anyone interested in this? Dave

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New plugin support
by Ian Piumarta 21 Jul '08

21 Jul '08

Hi, I'm about to commit (add) cross-platform directories to support GStreamerPlugin and OggPlugin. If anyone thinks this is a bad idea, please speak now. (FYI: the unix tree will also be getting ClipboardExtendedPlugin, DBusPlugin, RomePlugin and ImmX11Plugin in the same commit.) Cheers, Ian

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Profiling with gprof
by André Wendt 19 Jul '08

19 Jul '08

Hi, has anyone successfully profiled the VM with gprof lately, preferably on Linux? If so, how did you do it? I've tried the hints at http://wiki.squeak.org/squeak/2041 but I guess they're badly out of date: configure and GCC 4.2 will choke on '-g -pg -a' but not '-g -pg', and so there's no bb.out. What's worse is that gprof doesn't produce any statistics apart from vm/sqUnixMain.c -- here's its summary: Top 10 Lines: Line Count 239 1 934 1 977 1 1134 1 1159 1 1166 1 1279 1 What the... ? Hello, I was hoping for some details on the interpret() function!? -- Well, what more can possibly be in 430 KB of gmon.out? ;-) So how do I get gprof to take note of interp.c or gnu-interp.c? Thanks, André

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Events handling for SqueakGtk
by Gwenael Casaccio 13 Jul '08

13 Jul '08

Hello, I am the student who is working for the SqueakGtk plugin and I have a small problem. For the events handling there is an *active waiting system* like this : mainLoopProcess := [ [ [self doMainIteration. self doSignalProcessing] forkAt: Processor userBackgroundPriority + 1 ] repeat ] forkAt: Processor userBackgroundPriority It consumes a lot of cpu time. the problem is the method doMainIteration which call a C method to get an hypothetic event, I would like to replace this C method by an other method but this new method will block the interpreter until there is an event. To solve this problem I'll create a C thread and say to the vm change the status of the current process call the blocking method and when there is an event wake up the process to say I've finished my work. Is there a way to solve this problem ? Cheers, Gwenael

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Vm-dev July 2008