[GHC] #9989: GHCI is slow for precompiled code
GHC
ghc-devs at haskell.org
Mon Jan 19 15:55:14 UTC 2015
#9989: GHCI is slow for precompiled code
-------------------------------------+-------------------------------------
Reporter: remdezx | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: GHC API | Version: 7.8.3
Resolution: | Keywords:
Operating System: Linux | Architecture:
Type of failure: Runtime | Unknown/Multiple
performance bug | Test Case:
Blocked By: | Blocking:
Related Tickets: | Differential Revisions:
-------------------------------------+-------------------------------------
Description changed by simonpj:
Old description:
> Hello! We found that loading compiled and optimised `accelerate` code
> into ghci works much much slower than code run directly.
>
> (I'm marking it as a ghc-api bug, because I noticed this behavior while
> using it)
>
> Here is the example:
> {{{#!hs
> module Main where
>
> import Data.Array.Accelerate as A
> import Data.Array.Accelerate.CUDA as C
> import Data.Time.Clock (diffUTCTime, getCurrentTime)
>
> main :: IO ()
> main = do
> start <- getCurrentTime
> print $ C.run $ A.maximum $ A.map (+1) $ A.use (fromList (Z:.1000000)
> [1..1000000] :: Vector Double)
> end <- getCurrentTime
> print $ diffUTCTime end start
> }}}
>
> When I compile it and run
> {{
> $ ghc -O2 Main.hs -threaded
> [1 of 1] Compiling Main ( Main.hs, Main.o )
> Linking Main ...
> $ ./Main
> Array (Z) [1000001.0]
> 0.162204s
> }}
> It takes `0.16 s` to finish
> When I compile it and load into ghci:
> {{{
> $ ghc -O2 -dynamic -c Main.hs
> $ ghci
> GHCi, version 7.8.3: http://www.haskell.org/ghc/ :? for help
> Loading package ghc-prim ... linking ... done.
> Loading package integer-gmp ... linking ... done.
> Loading package base ... linking ... done.
> Prelude> :l Main
> Ok, modules loaded: Main.
> Prelude Main> main
> Loading package transformers-0.3.0.0 ... linking ... done.
> Loading package array-0.5.0.0 ... linking ... done.
> Loading package deepseq-1.3.0.2 ... linking ... done.
> Loading package bytestring-0.10.4.0 ... linking ... done.
> Loading package containers-0.5.5.1 ... linking ... done.
> Loading package binary-0.7.1.0 ... linking ... done.
> Loading package pretty-1.1.1.1 ... linking ... done.
> Loading package filepath-1.3.0.2 ... linking ... done.
> Loading package old-locale-1.0.0.6 ... linking ... done.
> Loading package time-1.4.2 ... linking ... done.
> Loading package unix-2.7.0.1 ... linking ... done.
> Loading package directory-1.2.1.0 ... linking ... done.
> Loading package process-1.2.0.0 ... linking ... done.
> Loading package stm-2.4.4 ... linking ... done.
> Loading package SafeSemaphore-0.10.1 ... linking ... done.
> Loading package mtl-2.1.3.1 ... linking ... done.
> Loading package template-haskell ... linking ... done.
> Loading package fclabels-2.0.2.2 ... linking ... done.
> Loading package text-1.1.1.3 ... linking ... done.
> Loading package hashable-1.2.3.1 ... linking ... done.
> Loading package primitive-0.5.4.0 ... linking ... done.
> Loading package vector-0.10.12.2 ... linking ... done.
> Loading package hashtables-1.2.0.1 ... linking ... done.
> Loading package unordered-containers-0.2.5.1 ... linking ... done.
> Loading package accelerate-0.15.0.0 ... linking ... done.
> Loading package byteable-0.1.1 ... linking ... done.
> Loading package cryptohash-0.11.6 ... linking ... done.
> Loading package cuda-0.6.5.1 ... linking ... done.
> Loading package exception-transformers-0.3.0.4 ... linking ... done.
> Loading package exception-mtl-0.3.0.5 ... linking ... done.
> Loading package old-time-1.1.0.2 ... linking ... done.
> Loading package polyparse-1.11 ... linking ... done.
> Loading package cpphs-1.18.6 ... linking ... done.
> Loading package haskell-src-exts-1.16.0.1 ... linking ... done.
> Loading package syb-0.4.4 ... linking ... done.
> Loading package th-lift-0.7 ... linking ... done.
> Loading package safe-0.3.8 ... linking ... done.
> Loading package th-expand-syns-0.3.0.4 ... linking ... done.
> Loading package th-reify-many-0.1.2 ... linking ... done.
> Loading package th-orphans-0.8.3 ... linking ... done.
> Loading package haskell-src-meta-0.6.0.8 ... linking ... done.
> Loading package srcloc-0.4.1 ... linking ... done.
> Loading package mainland-pretty-0.2.7 ... linking ... done.
> Loading package symbol-0.2.4 ... linking ... done.
> Loading package language-c-quote-0.8.0 ... linking ... done.
> Loading package accelerate-cuda-0.15.0.0 ... linking ... done.
> Array (Z) [1000001.0]
> 0.256128s
> }}}
> It takes `0.26 s` to finish. On other computer, using `criterion`, we
> observed even a `50x` difference.
>
> Why is it working so slow, isn't ghci just to load function and simply
> call it?
>
> Here is how execution time changes for different matrix sizes. For
> comparison we have also measured time of interpreted code (without
> precompiling).
>
> {{{
> size | compiled | precompiled | interpreted
> ---------+-----------+--------------+------------
> 100 | 0.054076s | 0.082686s | 0.151857s
> 1000 | 0.054509s | 0.08305s | 0.135452s
> 10000 | 0.055405s | 0.08469s | 0.12632s
> 100000 | 0.057768s | 0.093011s | 0.155359s
> 1000000 | 0.089811s | 0.251359s | 0.202022s
> 10000000 | 0.397642s | 1.400603s | 0.898547s
> }}}
>
> We believe that problem lies on the side of `ghci` rather than
> `accelerate`, how could we confirm this?
>
> Moreover and even more important is there any workaround for it, if we
> need this precompiled code running fast in production environment?
>
> Any guidance will be appreciated.
New description:
Hello! We found that loading compiled and optimised `accelerate` code into
ghci works much much slower than code run directly.
(I'm marking it as a ghc-api bug, because I noticed this behavior while
using it)
Here is the example:
{{{#!hs
module Main where
import Data.Array.Accelerate as A
import Data.Array.Accelerate.CUDA as C
import Data.Time.Clock (diffUTCTime, getCurrentTime)
main :: IO ()
main = do
start <- getCurrentTime
print $ C.run $ A.maximum $ A.map (+1) $ A.use (fromList (Z:.1000000)
[1..1000000] :: Vector Double)
end <- getCurrentTime
print $ diffUTCTime end start
}}}
When I compile it and run
{{{
$ ghc -O2 Main.hs -threaded
[1 of 1] Compiling Main ( Main.hs, Main.o )
Linking Main ...
$ ./Main
Array (Z) [1000001.0]
0.162204s
}}}
It takes `0.16 s` to finish
When I compile it and load into ghci:
{{{
$ ghc -O2 -dynamic -c Main.hs
$ ghci
GHCi, version 7.8.3: http://www.haskell.org/ghc/ :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Prelude> :l Main
Ok, modules loaded: Main.
Prelude Main> main
Loading package transformers-0.3.0.0 ... linking ... done.
Loading package array-0.5.0.0 ... linking ... done.
Loading package deepseq-1.3.0.2 ... linking ... done.
Loading package bytestring-0.10.4.0 ... linking ... done.
Loading package containers-0.5.5.1 ... linking ... done.
Loading package binary-0.7.1.0 ... linking ... done.
Loading package pretty-1.1.1.1 ... linking ... done.
Loading package filepath-1.3.0.2 ... linking ... done.
Loading package old-locale-1.0.0.6 ... linking ... done.
Loading package time-1.4.2 ... linking ... done.
Loading package unix-2.7.0.1 ... linking ... done.
Loading package directory-1.2.1.0 ... linking ... done.
Loading package process-1.2.0.0 ... linking ... done.
Loading package stm-2.4.4 ... linking ... done.
Loading package SafeSemaphore-0.10.1 ... linking ... done.
Loading package mtl-2.1.3.1 ... linking ... done.
Loading package template-haskell ... linking ... done.
Loading package fclabels-2.0.2.2 ... linking ... done.
Loading package text-1.1.1.3 ... linking ... done.
Loading package hashable-1.2.3.1 ... linking ... done.
Loading package primitive-0.5.4.0 ... linking ... done.
Loading package vector-0.10.12.2 ... linking ... done.
Loading package hashtables-1.2.0.1 ... linking ... done.
Loading package unordered-containers-0.2.5.1 ... linking ... done.
Loading package accelerate-0.15.0.0 ... linking ... done.
Loading package byteable-0.1.1 ... linking ... done.
Loading package cryptohash-0.11.6 ... linking ... done.
Loading package cuda-0.6.5.1 ... linking ... done.
Loading package exception-transformers-0.3.0.4 ... linking ... done.
Loading package exception-mtl-0.3.0.5 ... linking ... done.
Loading package old-time-1.1.0.2 ... linking ... done.
Loading package polyparse-1.11 ... linking ... done.
Loading package cpphs-1.18.6 ... linking ... done.
Loading package haskell-src-exts-1.16.0.1 ... linking ... done.
Loading package syb-0.4.4 ... linking ... done.
Loading package th-lift-0.7 ... linking ... done.
Loading package safe-0.3.8 ... linking ... done.
Loading package th-expand-syns-0.3.0.4 ... linking ... done.
Loading package th-reify-many-0.1.2 ... linking ... done.
Loading package th-orphans-0.8.3 ... linking ... done.
Loading package haskell-src-meta-0.6.0.8 ... linking ... done.
Loading package srcloc-0.4.1 ... linking ... done.
Loading package mainland-pretty-0.2.7 ... linking ... done.
Loading package symbol-0.2.4 ... linking ... done.
Loading package language-c-quote-0.8.0 ... linking ... done.
Loading package accelerate-cuda-0.15.0.0 ... linking ... done.
Array (Z) [1000001.0]
0.256128s
}}}
It takes `0.26 s` to finish. On other computer, using `criterion`, we
observed even a `50x` difference.
Why is it working so slow, isn't ghci just to load function and simply
call it?
Here is how execution time changes for different matrix sizes. For
comparison we have also measured time of interpreted code (without
precompiling).
{{{
size | compiled | precompiled | interpreted
---------+-----------+--------------+------------
100 | 0.054076s | 0.082686s | 0.151857s
1000 | 0.054509s | 0.08305s | 0.135452s
10000 | 0.055405s | 0.08469s | 0.12632s
100000 | 0.057768s | 0.093011s | 0.155359s
1000000 | 0.089811s | 0.251359s | 0.202022s
10000000 | 0.397642s | 1.400603s | 0.898547s
}}}
We believe that problem lies on the side of `ghci` rather than
`accelerate`, how could we confirm this?
Moreover and even more important is there any workaround for it, if we
need this precompiled code running fast in production environment?
Any guidance will be appreciated.
--
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9989#comment:3>
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