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| author | MarcelineVQ <matthewnhyatt@gmail.com> | 2015-12-19 11:10:54 +0100 |
|---|---|---|
| committer | Thomas Miedema <thomasmiedema@gmail.com> | 2015-12-19 11:10:58 +0100 |
| commit | b02838405b00bcdeebb44da0a7a9562cd7fda66b (patch) | |
| tree | 590b90460663933028aedea25c4ac09f251f83be /docs/users_guide/using-concurrent.rst | |
| parent | 2cc5b607df27e702541985f7c4c987806c4ec2a1 (diff) | |
| download | haskell-b02838405b00bcdeebb44da0a7a9562cd7fda66b.tar.gz | |
Add -Nmax<n> RTS feature (#10728)
Added maximum core use based on processors
-Nmax<x> chooses the minimum of processor count or x
Added documentation.
Reviewed By: simonmar, thomie
Differential Revision: https://phabricator.haskell.org/D1650
Diffstat (limited to 'docs/users_guide/using-concurrent.rst')
| -rw-r--r-- | docs/users_guide/using-concurrent.rst | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/docs/users_guide/using-concurrent.rst b/docs/users_guide/using-concurrent.rst index c00a294132..2621afce0f 100644 --- a/docs/users_guide/using-concurrent.rst +++ b/docs/users_guide/using-concurrent.rst @@ -107,11 +107,14 @@ RTS options for SMP parallelism There are two ways to run a program on multiple processors: call ``Control.Concurrent.setNumCapabilities`` from your program, or use the -RTS ``-N`` option. +RTS ``-N`` options. ``-N⟨x⟩`` +``-Nmax⟨x⟩`` + .. index:: single: -N⟨x⟩; RTS option + single: -Nmax(x); RTS option Use ⟨x⟩ simultaneous threads when running the program. @@ -133,6 +136,9 @@ RTS ``-N`` option. value of ⟨x⟩ itself based on how many processors are in your machine. + With Nmax⟨x⟩, i.e. ``+RTS -Nmax3 -RTS``, the runtime will choose at + most (x), also limited by the number of processors on the system. + Be careful when using all the processors in your machine: if some of your processors are in use by other programs, this can actually harm performance rather than improve it. |