具有堆栈runghc的多核并行性 [英] multicore parallelism with stack runghc

问题描述

我一直在研究脚本，希望在其中利用多种通过将mapM与 Async.mapConcurrently .

I had been working on a script in which I hoped to take advantage of multiple processors in my machine by swapping out mapM with Async.mapConcurrently.

在那种情况下，没有观察到速度增加，我想验证runghc确实可以利用多个内核.

Observing no speed increase in that instance, I wanted to verify that runghc can indeed utilize multiple cores.

提供文件Foo.hs:

import Control.Concurrent

main = print =<< Control.Concurrent.getNumCapabilities

如果我按如下方式编译文件:

If I compile the file as follows:

stack ghc -- -threaded Foo.hs

，然后按如下所示运行它:

and then run it as follows:

./Foo

它返回结果1.这是预期的，因为没有提供RTS选项.改为按以下方式运行它:

it returns the result 1. This is expected, as no RTS options have been supplied. Running it instead as follows:

./Foo +RTS -N

返回数字6，因为我的计算机中有6个处理器(同意nproc).

returns the number 6, as there are 6 processors in my machine (agreeing with nproc).

但是，当我像这样在解释模式"下运行脚本时:

However, when I run the script in "interpreted mode" like so:

GHCRTS="-N" stack runghc Foo.hs

它会产生以下错误文本:

It yields the following error text:

Running /home/kostmo/.stack/programs/x86_64-linux/ghc-nopie-8.0.2/bin/ghc-pkg --no-user-package-db list --global exited with ExitFailure 1

ghc-pkg: the flag -N requires the program to be built with -threaded

是否可以使用带有堆栈脚本"的多个内核?

Is it possible to utilize multiple cores with stack "scripts"?

推荐答案

感谢提出这个问题，我认为堆栈应该专门处理GHCRTS环境变量，并打开了这个问题

Thanks for asking this question, I think stack should handle the GHCRTS environment variable specially, and opened this issue https://github.com/commercialhaskell/stack/issues/3444 and made this change https://github.com/commercialhaskell/stack/pull/3445

不幸的是，它不能解决这种情况，因为runghc本身(ghc)将处理​​GHCRTS，并且它不是由线程运行时构建的.因此无法使用环境变量解决方案.

Unfortunately, it does not solve this case, because runghc itself (ghc) will process GHCRTS, and it is not built with the threaded runtime. So the environment variable solution cannot be used.

我认为应该为stack script --compile提供-with-rtsopts -N标志，但这似乎不起作用，需要进一步调查.这不适用于runghc，因为它使用了解释器.

I think it should be possible to provide -with-rtsopts -N flag to stack script --compile, but that doesn't seem to be working, needs further investigation. This doesn't work with runghc, because it uses the interpreter.

这篇关于具有堆栈runghc的多核并行性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！