{-# LANGUAGE CPP #-} {- Copyright (C) 2010 Dr. Alistair Ward This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. -} {- | [@AUTHOR@] Dr. Alistair Ward [@DESCRIPTION@] Determines the CPU-time, required to evaluate the specified pure expression. -} module ToolShed.System.TimePure( -- * Functions getCPUSeconds, printCPUSeconds ) where import qualified System.CPUTime import qualified System.IO {- The function used to force evaluation of the pure expression 'rnf', and the type-class which the polymorphic data must implement 'NFData', has been relocated from module "Control.Parallel.Strategies" to "Control.DeepSeq". -} #ifdef HAVE_DEEPSEQ import Control.DeepSeq(NFData, deepseq) #else import Control.Parallel(pseq) import Control.Parallel.Strategies(NFData, rnf) #endif {- | * Time the specified pure expression, returning the required number of CPU-seconds and the result, as a 'Pair'. * CAVEAT: as a side-effect, the expression is /deep/ evaluated. -} getCPUSeconds :: (Fractional seconds, NFData expression) => expression -- ^ Arbitrary polymorphic expression. -> IO (seconds, expression) -- ^ The original expression, tagged with the CPU-seconds taken. getCPUSeconds expression = do start <- System.CPUTime.getCPUTime end <- #ifdef HAVE_DEEPSEQ expression `deepseq` #else rnf expression `pseq` #endif System.CPUTime.getCPUTime return {-to IO-monad-} (fromInteger (end - start) / 1e12 {-convert from pico-seconds-}, expression) {- | * Print the time required by the specified pure expression. * CAVEAT: as a side-effect, the expression is /deep/ evaluated. -} printCPUSeconds :: NFData expression => expression -> IO expression printCPUSeconds expression = do (cpuSeconds, result) <- getCPUSeconds expression System.IO.hPutStrLn System.IO.stderr $ "CPU-seconds:\t" ++ show (cpuSeconds :: Double) return {-to IO-monad-} result