August 2017 - Pharo-users - lists.pharo.org

Re: [Pharo-users] Threads safety in Pharo
by Stephane Ducasse Aug. 4, 2017

Aug. 4, 2017

On Fri, Aug 4, 2017 at 7:06 PM, Alidra Abdelghani via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > > > ---------- Forwarded message ---------- > From: Alidra Abdelghani <alidrandco(a)yahoo.fr> > To: Guillermo Polito <guillermopolito(a)gmail.com> > Cc: Any question about pharo is welcome <pharo-users(a)lists.pharo.org>, > "StÃ©phane Ducasse" <stephane.ducasse(a)inria.fr>, farid arfi < > arfi_f(a)hotmail.com> > Bcc: > Date: Fri, 4 Aug 2017 19:06:00 +0200 > Subject: Re: [Pharo-users] Threads safety in Pharo > Thanks Guille for your answer, > From what I understand, it is mainly a synchronisation problem. Why cant' > existing synchronisation mechanisms (semaphores and mutex) be used? > They can but it means to analyse existing code and produce thread safe one. > Abdelghani > > > On 31 Jul 2017, at 18:44, Guillermo Polito <guillermopolito(a)gmail.com> > wrote: > > I believe there is no such a document. It would be however interesting to > investigate it a bit deeper. In general, the problem we talk about when we > talk about thread safety is the following: Can we run a workspace in a > separate thread than a browser and provide correct results? Can we run two > browsers concurrently and change code from both of them? > > The thread safety problem has several levels I'd say: > > - the kernel of the language (classes, methods, compilation, and so on) > cannot safely be modified while other threads are running. Thus, if we > compile a new version of a method in a thread, that could break a separate > thread that was using that method. > > - there are several libraries using global state. We should investigate > if they work correctly when using them concurrently. > E.g., source code management is not thread safe. This could cause a > source code corruption if several methods are modified concurrently. > Like that, we sh n ould investigate all libraries and see what should > be adapted and if there is a need at all. > > > - in a third level, general core libraries (collections, networking, > files, etc) are not designed to be thread safe and that is natural. For > example, most of the time you don't want that your collection is accessed > concurrently. For such cases, some libraries could provide some > extensions/wrappers/whatsoever to provide some synchronization mechanism. > Otherwise it is the responsibility of the user to synchronize usages with > semaphores/mutexes. > > > On Mon, Jul 31, 2017 at 1:38 AM, Alidra Abdelghani via Pharo-users < > pharo-users(a)lists.pharo.org> wrote: > >> >> >> ---------- Forwarded message ---------- >> From: Alidra Abdelghani <alidrandco(a)yahoo.fr> >> To: pharo-users(a)lists.pharo.org >> Cc: "StÃ©phane Ducasse" <stephane.ducasse(a)inria.fr>, farid arfi < >> arfi_f(a)hotmail.com> >> Bcc: >> Date: Mon, 31 Jul 2017 01:38:58 +0200 >> Subject: Threads safety in Pharo >> Hi, >> >> Somebody once evoked the problem of threads safety in Pharo. With a >> friend of mine who is expert in formal methods and process scheduling, we >> would like to have a look on it. >> Does anyone knows a good document describing the problem of Pharo with >> threads safety or at least any document that we can start with? >> >> Thanks in advance, >> Abdelghani >> >> >> >> > > > -- > > Guille Polito > > Research Engineer > French National Center for Scientific Research - *http://www.cnrs.fr* > <http://www.cnrs.fr/> > > > *Web:* *http://guillep.github.io* <http://guillep.github.io/> > *Phone: *+33 06 52 70 66 13 <+33%206%2052%2070%2066%2013> > > > >

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Re: [Pharo-users] Threads safety in Pharo
by Stephane Ducasse Aug. 4, 2017

Aug. 4, 2017

> > Great, I taught some of theses concepts to my students some times ago and we did some fun lab sessions with the Linux scheduler > > This was on my todo to turn it into a book chapter for Pharo. > > So may be we could work together to write a little booklet on this aspect to get started. > > > I would love to :D Be my guest. I can create a booklet in no time. I once started to collect notes on PharoLimbo/ConcurrencyBasics on github. Start there! Stef > > > Stef > > >

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Compiling lots of method source without debugger
by Patrick Scherer Aug. 4, 2017

Aug. 4, 2017

Hello everyone, This is my first time here so I hope this is the right place to ask questions. In an attempt to move lots of code from VA Smalltalk to Pharo, I need to compile a lot of methods whose code may or may not work due to missing classes in Pharo etc. I want to be able to compile these methods programatically without interruptions (using method source strings only) and gather all compiler errors that occur. What would be the best way to go about this? Also: How do I control in which package a compiled method ends up if the target class is in a different package (Method extension)? Any help would be greatly appreciated! Kind regards, Patrick Scherer

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Re: [Pharo-users] Threads safety in Pharo
by Guillermo Polito Aug. 4, 2017

Aug. 4, 2017

I believe there is no such a document. It would be however interesting to investigate it a bit deeper. In general, the problem we talk about when we talk about thread safety is the following: Can we run a workspace in a separate thread than a browser and provide correct results? Can we run two browsers concurrently and change code from both of them? The thread safety problem has several levels I'd say: - the kernel of the language (classes, methods, compilation, and so on) cannot safely be modified while other threads are running. Thus, if we compile a new version of a method in a thread, that could break a separate thread that was using that method. - there are several libraries using global state. We should investigate if they work correctly when using them concurrently. E.g., source code management is not thread safe. This could cause a source code corruption if several methods are modified concurrently. Like that, we should investigate all libraries and see what should be adapted and if there is a need at all. - in a third level, general core libraries (collections, networking, files, etc) are not designed to be thread safe and that is natural. For example, most of the time you don't want that your collection is accessed concurrently. For such cases, some libraries could provide some extensions/wrappers/whatsoever to provide some synchronization mechanism. Otherwise it is the responsibility of the user to synchronize usages with semaphores/mutexes. On Mon, Jul 31, 2017 at 1:38 AM, Alidra Abdelghani via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > > > ---------- Forwarded message ---------- > From: Alidra Abdelghani <alidrandco(a)yahoo.fr> > To: pharo-users(a)lists.pharo.org > Cc: "StÃ©phane Ducasse" <stephane.ducasse(a)inria.fr>, farid arfi < > arfi_f(a)hotmail.com> > Bcc: > Date: Mon, 31 Jul 2017 01:38:58 +0200 > Subject: Threads safety in Pharo > Hi, > > Somebody once evoked the problem of threads safety in Pharo. With a friend > of mine who is expert in formal methods and process scheduling, we would > like to have a look on it. > Does anyone knows a good document describing the problem of Pharo with > threads safety or at least any document that we can start with? > > Thanks in advance, > Abdelghani > > > > -- Guille Polito Research Engineer French National Center for Scientific Research - *http://www.cnrs.fr* <http://www.cnrs.fr> *Web:* *http://guillep.github.io* <http://guillep.github.io> *Phone: *+33 06 52 70 66 13

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How to remove packages and reclaim image size?
by Tim Mackinnon Aug. 4, 2017

Aug. 4, 2017

Hi - Iâm wondering how you best remove packages in the image to reclaim space? I am a bit confused because I see 2 package systems MCPackage and RPackage? And I see 2 different ways of removing things: (MCPackage named: name) unload (RPackage organizer packageNamed: name) unregister So which is the correct one to use (or are they the same?). Iâve tried both, but then when I save my image (headless in a script) - it doesnât seem to make any difference in image size. So Iâm also wondering if there is an extra step to forcing size reduction. I have tried: 3 timesRepeat: [ Smalltalk garbageCollect. Smalltalk cleanOutUndeclared. Smalltalk fixObsoleteReferences]. Which is what I saw in some ImageCleaner tool, but again I donât see any image size difference, which makes me wonder if Iâm doing the wrong thing or missing a step? Tim

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Glorp reconnection management (was: Re: Glorp: how to reconnect after image shutdown / load?)
by Herby VojÄÃk Aug. 4, 2017

Aug. 4, 2017

jtuchel(a)objektfabrik.de wrote: > Herby, > > I am not aware of any automatic reconnect tools. Kepping a DB connection > alive after an image is closed is surely not desired and chances are the > DB will close the inactive session eventually anyways. Hm. When I though about it, image save / load cycle is just one example of losing a connection to db. So the question is more on "how to manage possible disconnections / reconnections"? > So it's probably best to make the DB connections reconnect on demand. > That means that whenever you open a session, check if a DB connection is > available or establish a new one otherwise. Hm, I though that once I open a session it does actually connect on demand (it has Login, system and all the information for it). Does it actually mean that if I want to stay connected I must do `session login` before each `session inUnitOfWorkDo:`? > There are many scenarios that can lead to the loss of a DB connection > that you usually cannot influence (network connection drops, DB server > has some error condition etc.) , so this is a good idea anyways. As written above, I thought glorp manages this kind of reconnection itself. If not, can someone point me to the some example where this is managed? I am asking because in Glorp book I did not find anything about this (I have read it). Thanks, Herby > HTH > > Joachim > > > Am 01.08.17 um 22:29 schrieb Herby VojÄÃk: >> Hello! >> >> ZnServers have its own register mechanism by which they listen when >> they are tagged as such after image save and load. >> >> I wonder if there is some way to connect to database in Glorp and then >> "keep the connection" between image save/load. Or how is this managed >> notmally in apps that use databases? Is image "preconfigured" with >> live self-healing connection or does some special piece of startup >> code be installed so it runs after deployment and image start? >> >> Thanks, Herby >> >> > >

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Re: [Pharo-users] Threads safety in Pharo
by Alidra Abdelghani Aug. 4, 2017

Aug. 4, 2017

> On 01 Aug 2017, at 09:36, StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> wrote: > > To complement. > > What would be fun is to investigate the implementation of ProcessScheduler, Process and check the implementation. > > Abdel there is a nice presentation of the processor and process in the Squeak french book. Great, I taught some of theses concepts to my students some times ago and we did some fun lab sessions with the Linux scheduler > This was on my todo to turn it into a book chapter for Pharo. > > So may be we could work together to write a little booklet on this aspect to get started. I would love to :D > > Stef

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Iceberg and removing packages
by Esteban A. Maringolo Aug. 4, 2017

Aug. 4, 2017

Hi, I'm playing around with Iceberg in Pharo 6, and even when I find the workflow streamlined, but since it doesn't map 1:1 with git workflow from other IDEs or command line, I find myself not knowing how to do certain tasks. One thing that happened is that I published a few packages to one of my repos in Github, then I decided to remove one of the packages from the repo, then I synchronized it but in the repo there is still is the package folder for the package I removed. What should I do to definitely remove those files from the commit? Regards! Esteban A. Maringolo

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Settings - Server Mode - should I use it?
by Tim Mackinnon Aug. 4, 2017

Aug. 4, 2017

Hi - I hadnât looked in the settings browser much before, but I was looking at what settings there were and noticed âserver modeâ. Should I be enabling this when building a headless server image to run on Lambda? I saw a 2016 post by John Brant that indicated it made a difference when doing some benchmarking in the image (presumably headful) - but Iâm wondering if when running headless on a server whether it really makes a difference. Has anyone played with this much before? Tim

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Syntax Error: Message pattern expected
by jb Aug. 4, 2017

Aug. 4, 2017

Hi everyone! I get this error when I try to load a package from my Monticello rep. I have never seen this before and have not a clue where to look for the mistake. The error message window show: Object <none> Any hints what to do? Johannes -- View this message in context: http://forum.world.st/Syntax-Error-Message-pattern-expected-tp4958351.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

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