I just stumbled upon this old post that mentions Java heap space and how to change its parameters in Eclipse (in the eclipse.ini file). How do I do set these in the new VSCode environment?
The Eclipse environment is quite different from the VScode environment. Everything runs in a single JVM there, and so it was difficult for plugin writers to programmatically increase the heap size. This led to writing manual pages on the topic.
In VScode we have a JVM for every Rascal process:
for every terminal REPL there is one JVM
for the Rascal LSP server there is one JVM
for the generic DSL-parametrized LSP server there is one JVM
there is one JVM for every deployed DSL server written in Rascal
And the extension code starts these JVMs, so we can control how much memory they receive. The latest release does this by assessing the total available memory on your machine and allocating a sumptuous amount for every process.
And so there is no configuration option for the user anymore, as we had to add for the Eclipse situation.
Related
I am writing an F# port of a program I wrote in native code in the past. I used BenchmarkDotNet to measure its performance. I also placed a native EXE in the application's output directory.
I set my native program as the baseline benchmark and saw it was 5x faster than my F# program. Just as I expected!
However, the native program is posted on GitHub and distributed as a Win64 binary only. In case somebody using another OS tries to run it, it will crash.
So, how to specify that this benchmark will only run on 64-bit Windows?
In BenchmarkDotNet, there is a concept of Jobs. Jobs define how the benchmark should be executed.
So, you can express your "x64 only" condition as a job. Note that there are several different 64x jit-compilers depends on runtime (LegacyJIT-x64 and RyuJIT-x64 for the full .NET Framework, RyuJIT-x64 for .NET Core, and Mono JIT compiler). You can request not only a specific platform but also a specific JIT-compiler (it can significantly affect performance), e.g.:
[<RyuJitX64Job>]
member this.MyAwesomeBenchmark () = // ...
In this case, a user will be notified that it's impossible to compile the benchmark for required platform.
Unfortunately, there is no way to require a specific OS for now (there is only one option: current OS). So, in your case, it's probably better to check System.Environment.Is64BitOperatingSystem and System.Environment.OSVersion at the start and don't run benchmarks on invalid operation systems.
I have big grails project (five modules + 2 custom no pre-compiled plugins).
At first – compilation was failed with out of memory in javac. I added as params:
-J-Xmx1024m -J-Xms512m -J-XX:MaxPermSize=2048m
great, first OOM – fixed.
At second – I have OOM in groovy compiler. How to pass memory params from Idea to groovyc? Also my application should work in NOT forking mode
You don't set the groovyc memory directly.
You should set/increase your memory settings directly in the IntelliJ settings.
The documentation can be found here: https://www.jetbrains.com/idea/help/increasing-memory-heap.html
In general, in your IntelliJ installation's bin folder, there will be 2 files of interest: idea.exe.vmoptions and idea64.exe.vmoptions. You would adjust the settings for the file that matches the idea.exe or idea64.exe you use to launch IntelliJ
Within the file, you can adjust your heap memory for IntelliJ as a whole. My guess is you are running out of perm gen space and should increase your MaxPermGenSize. The settings would looks similar to this (I have 16gb memory on my PC):
-Xms750m
-Xmx2g
-XX:MaxPermSize=350m
How can I build and compile my own Lua files on Windows? And make them executable.
I am reading Beginning Lua programming, and I have Windows 7 and MacOS Lion both installed. I am having the hard time to follow the instructions. They do not work for me.
On MacOS I open the terminal and put these in:
export LUA_DIR=/usr/local/lib/lua/5.1
mkdir -p /usr/local/lib/lua/5.1 (it tells me, mkdir: illegal option) and I can not follow from here
SET LUA_DIR=”c:\program files\lua\5.1”
As for Windows I do this according to the book.
This what I see in my shell c:\Users\bd>
mkdir "c:\program files\utility" and it tells me access is denied
I have tried to right click on this folder and check off read only, but it does not work.
Any clues would be appreciated, this part has been really confusing for me.
To package your Lua files into an executable on Windows you have several options. There is srlua, there is wxLuaFreeze from wxLua (available as a binary for Windows), and there are more options in this SO answer.
Essentially, the main two options are: (1) append your Lua code to a precompiled exe file, such that it will be loaded and executed when that exe file is run, and (2) convert your Lua code into real executable by compiling it to bytecode, then to C, and then to your target platform.
As to your MacOS issue, mkdir -p means that mkdir is asked to create intermediate directories (for example, you asked to create /a/b/c, it will also create /a/b if those don't exist). As you don't say which version of MacOS you run, it's difficult to provide more detailed answer.
For now the standard distribution of Lua does not compile a script to native executable code; it execute your scripts by first compiling it to bytecode, then by interpreting the bytecode with a reasonnably fast static interpret (this also means that it is easily portable across native or virtual systems, and very resistant to attacks (that could be targetting bugs in the native compiler itself).
Also Lua still does not feature a runtime JIT compiler like Java and .Net: Lua still does not features a VM to produce a safe sandbox.
There exists Lua packages that convert your bytecode (or directly a source script) to a C source that can be used to convert a Lua library into native mode via the same C compiler used to compile the Lua engine itself (this is how the builtin libraries are produced, though they are slightly optimized manually in some time-critical parts).
However it is possible to compile Lua to a javascript source, and run it with fast performance using Javascript, because today's Javascript interprets do have good performance with their implemented VM featuring a JIT compiler for their own bytecodes.
It is also possible by converting it the Lua bytecode to a .Net or Java source that can then be executed directly from Lua (for that you need a version of Lua that has been ported to .Net or Java or Javascript, something that is not so complicate than developing in C/C++ directly a VM with a JIT compiler (a moderately complex part is the bytecode verifier, but the really complex part is the memory manager its garbage collector and its sandbox so that your Lua script will be fully isolated from the Lua engine itself for itw own memory, but the most complex part if the runtime optimizer and collection of profiling statistics: this has been done in the modern VMs for Java, .Net, Javascript, PHP/Zend, Python, Perl...).
I dont know which other language VM would offer the best performance to port Lua and implement on it a compiler to their own bytecode running at near native speed in their VM. But my own small experience with programs (in a much simpler language) self-generating a bytecode that they can run themselves, has always shown me Java winning in performance over .Net and Javascript. This is most probably because Java features an profiling-based dynamic code optimizer
(On the opposite the .Net optimizer runs only once during program installation, using some profiling data collected during the installation of the .Net VM itself, or at first instanciation of the script, without really knowing any profiling data collected during execution of the compiled program itself, and based on some cheked assumptions about the platform capabilities).
I also don't if would be faster in PHP, Python or Perl; the comparison with newer Javascript engines was never attempted though. Porting/compiling a Lua program to Javascript is relatively easy because it implements closures relatively easy for the resolution of linkages. Then the generated Javascript will compile to native code with the excellent Javascript's JIT compilers we have today (and never cease to improve in performance, so much that I've seen various appliactions running now faster in Javascript than before when they were written in C++ or plain C; as well the memory footprint has largely been reduced, we no longer have memory leaks, and even if there's a garbage collector, today's Javascript VM have a very efficient one, which is even better than the GC implemented in the native Lua).
But Lua remains useful as it is easy to secure and sandbox and offers various security benefits (but there are security issues in Lua as well for some kinds of applications, where Javascript offers some solutions, notably for side-channel attacks based on variation of time of execution; but these side-channel attacks are very hard to solve and can affect any system, any program, any programming language, and this starts becoming a critical issue because they are now more esily exploitable; the reason of that comes from hardware optimizations that we depend more and more today when we want to maximize the performances). And with Lua you may be more immune to these problems that a sandboxing sofware environment cannot solve alone.
Probably later we'll see a true VM implementation of Lua with a JIT and self-generating code and the possibility to instanciate new sandboxed VMs to run their self-generated code. It will take more time to generate an EXE file for distribution; notably because it generally requires adding also an installer and a distribution manager.
So for now we could imagine distributing Lua applications compiled to the bytecode of another JIT-capable VM: this generated bytecode would be faster than the Lua bytecode, and would then be extremely complex to reverse-engineer to the semantics of Lua because it would require two separate reverse engineering first from the bytecode of the other VM to the bytecode of Lua, both bytecodes loosing some easiy inferable rules and options tested and foll, and then again to sme Lua source
For the OSX terminal issue:
This command should work
export LUA_DIR=/usr/local/lib/lua/5.1
This command will probably give you permission problems:
mkdir -p /usr/local/lib/lua/5.1
You may try this to solve that. You will be prompted for your password:
sudo mkdir -p /usr/local/lib/lua/5.1
This command has nothing to do with OSX and will not work. This is a windows command:
SET LUA_DIR=”c:\program files\lua\5.1”
You have a permissions problem with Windows- try creating your cmd or PowerShell in Administrator mode. C:\Program Files is a protected directory that a regular user account doesn't have permission to write to.
As for the OS X issue, check out the mkdir OS X manual page to make sure you have the command correct.
So, if I understood your question correctly, you are trying to build Lua on Windows.
This is of course possible, but not easy for beginners. I would highly recommend you to use a binary distribution, which is much easier to install, unless you have special requirements.
Here are several Windows distributions :
Lua Binaries (Lua 5.1 and 5.2)
LuaForWindows (Lua 5.1)
LuaDist (Lua 5.2)
I've done some search out there but couldn't find too much really helpful info on it, but could someone try to explain the basic of Java memory maps? Like where/how to use it, it's purpose, and maybe some syntax examples (inputs/outputs types)? I'm taking a Java test soon and this could be one of the topics, but through all of my tutorials Jmap has not come up. Thanks in advance
Edit: I'm referring to the tool: jmap
I would read the man page you have referenced.
jmap prints shared object memory maps or heap memory details of a given process or core file or a remote debug server.
NOTE: This utility is unsupported and may or may not be available in future versions of the JDK. In Windows Systems where dbgeng.dll is not present, 'Debugging Tools For Windows' needs to be installed to have these tools working. Also, PATH environment variable should contain the location of jvm.dll used by the target process or the location from which the Crash Dump file was produced.
http://docs.oracle.com/javase/7/docs/technotes/tools/share/jmap.html
Its not a tool to be played with lightly. You need a good profiler which can read it output as jhat is only useful for trivial programs. (YourKit works just fine for 1+ GB heaps)
I'm developing on the standard Lift platform (maven and jetty). I'm repeatedly (once every couple of days) getting this:
Exception in thread "7048009#qtp-3179125-12" java.lang.OutOfMemoryError: PermGen space
2009-09-15 19:41:38.629::WARN: handle failed
java.lang.OutOfMemoryError: PermGen space
This is in my dev environment. It's not a problem because I can keep restarting the server. In deployment I'm not having these problems so it's not a real issue. I'm just curious.
I don't know too much about the JVM. I think I'm correct in thinking that permanent generation memory is for things like classes and interned strings? What I remember is a bit mixed up with the .NET memory model...
Any reason why this is happening? Are the defaults just crazily low? Is it to do with all the auxiliary objects that Scala has to create for Function objects and similar FP things? Every time I restart Jetty with newly written code (every few minutes) I imagine it re-loads classes etc. But even so, it cant' be that many can it? And shouldn't the JVM be able to deal with a large number of classes?
Cheers
Joe
From this post:
This exception occurred for one simple reason :
the permgenspace is where class properties, such as methods, fields, annotations, and also static variables, etc. are stored in the Java VM, but this space has the particularity to not being cleaned by the garbage collector.
So if your webapp uses or creates a lot of classes (I’m thinking dynamic generations of classes), chances are you met this problem.
Here are some solutions that helped me get rid of this exception :
-XX:+CMSClassUnloadingEnabled : this setting enables garbage collection in the permgenspace
-XX:+CMSPermGenSweepingEnabled : allows the garbage collector to remove even classes from the memory
-XX:PermSize=64M -XX:MaxPermSize=128M : raises the amount of memory allocated to the permgenspace
May be this could help.
Edit July 2012 (almost 3 years later):
Ondra Žižka comments (and I have updated the answer above):
JVM 1.6.0_27 says: Please use:
CMSClassUnloadingEnabled (Whether class unloading enabled when using CMS GC)
in place of CMSPermGenSweepingEnabled in the future
See the full Hotspot JVM Options - The complete reference for mroe.
If you see this when running mvn jetty:run,
set the MAVEN_OPTS.
For Linux:
export MAVEN_OPTS="-XX:+CMSClassUnloadingEnabled -XX:PermSize=256M -XX:MaxPermSize=512M"
mvn jetty:run
For Windows:
set "MAVEN_OPTS=-XX:+CMSClassUnloadingEnabled -XX:PermSize=256M -XX:MaxPermSize=512M"
mvn jetty:run
Should be fine now. If not, increase -XX:MaxPermSize.
You can also put these permanently to your environment.
For Linux, append the export line to ~/.bashrc
For Windows, press Win-key + PrintScreen, and go Advanced > Environment.
See also http://support.microsoft.com/kb/310519.
This is because of the reloading of classes as you suggested. If you are using lots of libraries etc. the sum of classes will rapidly grow for each restart. Try monitoring your jetty instance with VisualVM to get an overview of memory consumption when reloading.
The mailing list (http://groups.google.com/group/liftweb/) is the official support forum for Lift, and where you'll be able to get a better answer. I don't know the particulars of your dev setup (you don't go into much detail), but I assume you're reloading your war in Jetty without actually restarting it. Lift doesn't perform dynamic class generation (as suggested by VonC above), but Scala compiles each closure as a separate class. If you're adding and removing closures to your code over the course of several days, it's possible that too many classes are being loaded and never unloaded and taking up perm space. I'd suggest you enable the options JVM options mentioned by VonC above and see if they help.
The permanent generation is where the JVM puts stuff that will probably not be (garbage) collected like custom classloaders.
Depending on what you are deploying, the perm gen setting can be low. Some applications and/or containers combination do contain some memory leaks, so when an app gets undeployed sometimes some stuff like class loaders are not collected, resulting in filling the Perm Space thus generating the error you are having.
Unfortunately, currently the best option in this case is to max up the perm space with the following jvm flag (example for 192m perm size):
-XX:MaxPermSize=192M (or 256M)
The other option is to make sure that either the container or the framework do not leak memory.