{- | Module: Test.Tasty.Bench Copyright: (c) 2021 Andrew Lelechenko Licence: MIT Featherlight benchmark framework (only one file!) for performance measurement with API mimicking [@criterion@](http://hackage.haskell.org/package/criterion) and [@gauge@](http://hackage.haskell.org/package/gauge). A prominent feature is built-in comparison against baseline. === How lightweight is it? There is only one source file "Test.Tasty.Bench" and no external dependencies except [@tasty@](http://hackage.haskell.org/package/tasty). So if you already depend on @tasty@ for a test suite, there is nothing else to install. Compare this to @criterion@ (10+ modules, 50+ dependencies) and @gauge@ (40+ modules, depends on @basement@ and @vector@). === How is it possible? Our benchmarks are literally regular @tasty@ tests, so we can leverage all existing machinery for command-line options, resource management, structuring, listing and filtering benchmarks, running and reporting results. It also means that @tasty-bench@ can be used in conjunction with other @tasty@ ingredients. Unlike @criterion@ and @gauge@ we use a very simple statistical model described below. This is arguably a questionable choice, but it works pretty well in practice. A rare developer is sufficiently well-versed in probability theory to make sense and use of all numbers generated by @criterion@. === How to switch? allow to taste @tasty-bench@ instead of @criterion@ or @gauge@ without changing a single line of code: > cabal-version: 2.0 > > benchmark foo > ... > build-depends: > tasty-bench > mixins: > tasty-bench (Test.Tasty.Bench as Criterion) This works vice versa as well: if you use @tasty-bench@, but at some point need a more comprehensive statistical analysis, it is easy to switch temporarily back to @criterion@. === How to write a benchmark? Benchmarks are declared in a separate section of @cabal@ file: > cabal-version: 2.0 > name: bench-fibo > version: 0.0 > build-type: Simple > synopsis: Example of a benchmark > > benchmark bench-fibo > main-is: BenchFibo.hs > type: exitcode-stdio-1.0 > build-depends: base, tasty-bench And here is @BenchFibo.hs@: > import Test.Tasty.Bench > > fibo :: Int -> Integer > fibo n = if n < 2 then toInteger n else fibo (n - 1) + fibo (n - 2) > > main :: IO () > main = defaultMain > [ bgroup "fibonacci numbers" > [ bench "fifth" $ nf fibo 5 > , bench "tenth" $ nf fibo 10 > , bench "twentieth" $ nf fibo 20 > ] > ] Since @tasty-bench@ provides an API compatible with @criterion@, one can refer to for more examples. === How to read results? Running the example above (@cabal@ @bench@ or @stack@ @bench@) results in the following output: > All > fibonacci numbers > fifth: OK (2.13s) > 63 ns ± 3.4 ns > tenth: OK (1.71s) > 809 ns ± 73 ns > twentieth: OK (3.39s) > 104 μs ± 4.9 μs > > All 3 tests passed (7.25s) The output says that, for instance, the first benchmark was repeatedly executed for 2.13 seconds (wall time), its mean time was 63 nanoseconds and, assuming ideal precision of a system clock, execution time does not often diverge from the mean further than ±3.4 nanoseconds (double standard deviation, which for normal distributions corresponds to probability). Take standard deviation numbers with a grain of salt; there are lies, damned lies, and statistics. Note that this data is not directly comparable with @criterion@ output: > benchmarking fibonacci numbers/fifth > time 62.78 ns (61.99 ns .. 63.41 ns) > 0.999 R² (0.999 R² .. 1.000 R²) > mean 62.39 ns (61.93 ns .. 62.94 ns) > std dev 1.753 ns (1.427 ns .. 2.258 ns) One might interpret the second line as saying that 95% of measurements fell into 61.99–63.41 ns interval, but this is wrong. It states that the of execution time (which is not exactly the mean time) is most probably somewhere between 61.99 ns and 63.41 ns, but does not say a thing about individual measurements. To understand how far away a typical measurement deviates you need to add\/subtract double standard deviation yourself (which gives 62.78 ns ± 3.506 ns, similar to @tasty-bench@ above). To add to the confusion, @gauge@ in @--small@ mode outputs not the second line of @criterion@ report as one might expect, but a mean value from the penultimate line and a standard deviation: > fibonacci numbers/fifth mean 62.39 ns ( +- 1.753 ns ) The interval ±1.753 ns answers for of samples only, double it to estimate the behavior in 95% of cases. === Statistical model Here is a procedure used by @tasty-bench@ to measure execution time: 1. Set \( n \leftarrow 1 \). 2. Measure execution time \( t_n \) of \( n \) iterations and execution time \( t_{2n} \) of \( 2n \) iterations. 3. Find \( t \) which minimizes deviation of \( (nt, 2nt) \) from \( (t_n, t_{2n}) \). 4. If deviation is small enough (see @--stdev@ below), return \( t \) as a mean execution time. 5. Otherwise set \( n \leftarrow 2n \) and jump back to Step 2. This is roughly similar to the linear regression approach which @criterion@ takes, but we fit only two last points. This allows us to simplify away all heavy-weight statistical analysis. More importantly, earlier measurements, which are presumably shorter and noisier, do not affect overall result. This is in contrast to @criterion@, which fits all measurements and is biased to use more data points corresponding to shorter runs (it employs \( n \leftarrow 1.05n \) progression). An alert reader could object that we measure standard deviation for samples with \( n \) and \( 2n \) iterations, but report it scaled to a single iteration. Strictly speaking, this is justified only if we assume that deviating factors are either roughly periodic (e. g., coarseness of a system clock, garbage collection) or are likely to affect several successive iterations in the same way (e. g., slow down by another concurrent process). Obligatory disclaimer: statistics is a tricky matter, there is no one-size-fits-all approach. In the absence of a good theory simplistic approaches are as (un)sound as obscure ones. Those who seek statistical soundness should rather collect raw data and process it themselves using a proper statistical toolbox. Data reported by @tasty-bench@ is only of indicative and comparative significance. === Memory usage Passing @+RTS@ @-T@ (via @cabal@ @bench@ @--benchmark-options@ @\'+RTS@ @-T\'@ or @stack@ @bench@ @--ba@ @\'+RTS@ @-T\'@) enables @tasty-bench@ to estimate and report memory usage such as allocated and copied bytes: > All > fibonacci numbers > fifth: OK (2.13s) > 63 ns ± 3.4 ns, 223 B allocated, 0 B copied > tenth: OK (1.71s) > 809 ns ± 73 ns, 2.3 KB allocated, 0 B copied > twentieth: OK (3.39s) > 104 μs ± 4.9 μs, 277 KB allocated, 59 B copied > > All 3 tests passed (7.25s) === Combining tests and benchmarks When optimizing an existing function, it is important to check that its observable behavior remains unchanged. One can rebuild both tests and benchmarks after each change, but it would be more convenient to run sanity checks within benchmark itself. Since our benchmarks are compatible with @tasty@ tests, we can easily do so. Imagine you come up with a faster function @myFibo@ to generate Fibonacci numbers: > import Test.Tasty.Bench > import Test.Tasty.QuickCheck -- from tasty-quickcheck package > > fibo :: Int -> Integer > fibo n = if n < 2 then toInteger n else fibo (n - 1) + fibo (n - 2) > > myFibo :: Int -> Integer > myFibo n = if n < 3 then toInteger n else myFibo (n - 1) + myFibo (n - 2) > > main :: IO () > main = Test.Tasty.Bench.defaultMain -- not Test.Tasty.defaultMain > [ bench "fibo 20" $ nf fibo 20 > , bench "myFibo 20" $ nf myFibo 20 > , testProperty "myFibo = fibo" $ \n -> fibo n === myFibo n > ] This outputs: > All > fibo 20: OK (3.02s) > 104 μs ± 4.9 μs > myFibo 20: OK (1.99s) > 71 μs ± 5.3 μs > myFibo = fibo: FAIL > *** Failed! Falsified (after 5 tests and 1 shrink): > 2 > 1 /= 2 > Use --quickcheck-replay=927711 to reproduce. > > 1 out of 3 tests failed (5.03s) We see that @myFibo@ is indeed significantly faster than @fibo@, but unfortunately does not do the same thing. One should probably look for another way to speed up generation of Fibonacci numbers. === Troubleshooting If benchmark results look malformed like below, make sure that you are invoking 'Test.Tasty.Bench.defaultMain' and not 'Test.Tasty.defaultMain' (the difference is 'consoleBenchReporter' vs. 'consoleTestReporter'): > All > fibo 20: OK (1.46s) > Response {respEstimate = Estimate {estMean = Measurement {measTime = 87496728, measAllocs = 0, measCopied = 0}, estSigma = 694487}, respIfSlower = FailIfSlower {unFailIfSlower = Infinity}, respIfFaster = FailIfFaster {unFailIfFaster = Infinity}} === Comparison against baseline One can compare benchmark results against an earlier baseline in an automatic way. To use this feature, first run @tasty-bench@ with @--csv@ @FILE@ key to dump results to @FILE@ in CSV format: > Name,Mean (ps),2*Stdev (ps) > All.fibonacci numbers.fifth,48453,4060 > All.fibonacci numbers.tenth,637152,46744 > All.fibonacci numbers.twentieth,81369531,3342646 Note that columns do not match CSV reports of @criterion@ and @gauge@. If desired, missing columns can be faked with @awk@ @\'BEGIN@ @{FS=\",\";OFS=\",\"};@ @{print@ @$1,$2,$2,$2,$3\/2,$3\/2,$3\/2}\'@ or similar. Now modify implementation and rerun benchmarks with @--baseline@ @FILE@ key. This produces a report as follows: > All > fibonacci numbers > fifth: OK (0.44s) > 53 ns ± 2.7 ns, 8% slower than baseline > tenth: OK (0.33s) > 641 ns ± 59 ns > twentieth: OK (0.36s) > 77 μs ± 6.4 μs, 5% faster than baseline > > All 3 tests passed (1.50s) You can also fail benchmarks, which deviate too far from baseline, using @--fail-if-slower@ and @--fail-if-faster@ options. For example, setting both of them to 6 will fail the first benchmark above (because it is more than 6% slower), but the last one still succeeds (even while it is measurably faster than baseline, deviation is less than 6%). Consider also using @--hide-successes@ to show only problematic benchmarks, or even [@tasty-rerun@](http://hackage.haskell.org/package/tasty-rerun) package to focus on rerunning failing items only. === Command-line options Use @--help@ to list command-line options. [@-p@, @--pattern@]: This is a standard @tasty@ option, which allows filtering benchmarks by a pattern or @awk@ expression. Please refer to [@tasty@ documentation](https://github.com/feuerbach/tasty#patterns) for details. [@-t@, @--timeout@]: This is a standard @tasty@ option, setting timeout for individual benchmarks in seconds. Use it when benchmarks tend to take too long: @tasty-bench@ will make an effort to report results (even if of subpar quality) before timeout. Setting timeout too tight (insufficient for at least three iterations) will result in a benchmark failure. [@--stdev@]: Target relative standard deviation of measurements in percents (1% by default). Large values correspond to fast and loose benchmarks, and small ones to long and precise. If it takes far too long, consider setting @--timeout@, which will interrupt benchmarks, potentially before reaching the target deviation. [@--csv@]: File to write results in CSV format. [@--baseline@]: File to read baseline results in CSV format (as produced by @--csv@). [@--fail-if-slower@, @--fail-if-faster@]: Upper bounds of acceptable slow down \/ speed up in percents. If a benchmark is unacceptably slower \/ faster than baseline (see @--baseline@), it will be reported as failed. Can be used in conjunction with a standard @tasty@ option @--hide-successes@ to show only problematic benchmarks. -} {-# LANGUAGE CPP #-} {-# LANGUAGE DeriveDataTypeable #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE TupleSections #-} module Test.Tasty.Bench ( -- * Running 'Benchmark' defaultMain , Benchmark , bench , bgroup , env , envWithCleanup -- * Creating 'Benchmarkable' , Benchmarkable , nf , whnf , nfIO , whnfIO , nfAppIO , whnfAppIO -- * Ingredients , benchIngredients , consoleBenchReporter , csvReporter , RelStDev(..) , FailIfSlower(..) , FailIfFaster(..) ) where import Prelude hiding (Int, Integer) import Control.Applicative import Control.DeepSeq import Control.Exception import Control.Monad (void, unless, guard, (>=>)) import Data.Data (Typeable) import Data.Foldable (foldMap, traverse_) import Data.Int (Int64) import Data.IntMap (IntMap) import qualified Data.IntMap as IM import Data.List (intercalate, stripPrefix, isPrefixOf) import Data.Monoid (All(..), Any(..)) import Data.Proxy #if MIN_VERSION_containers(0,5,0) import Data.Set (lookupGE) #endif import qualified Data.Set as S import Data.Traversable (forM) import Data.Word (Word64) import GHC.Conc #if MIN_VERSION_base(4,6,0) import GHC.Stats #endif import System.CPUTime import System.Mem import Test.Tasty hiding (defaultMain) import qualified Test.Tasty import Test.Tasty.Ingredients import Test.Tasty.Ingredients.ConsoleReporter import Test.Tasty.Options import Test.Tasty.Providers import Test.Tasty.Runners import Text.Printf import System.IO import System.IO.Unsafe -- | In addition to @--stdev@ command-line option, -- one can adjust target relative standard deviation -- for individual benchmarks and groups of benchmarks -- using 'adjustOption' and 'localOption'. -- -- E. g., set target relative standard deviation to 2% as follows: -- -- > localOption (RelStDev 0.02) (bgroup [...]) -- newtype RelStDev = RelStDev Double deriving (Show, Read, Typeable) instance IsOption RelStDev where defaultValue = RelStDev 0.01 parseValue = fmap RelStDev . parsePositivePercents optionName = pure "stdev" optionHelp = pure "Target relative standard deviation of measurements in percents (1 by default). Large values correspond to fast and loose benchmarks, and small ones to long and precise. If it takes far too long, consider setting --timeout, which will interrupt benchmarks, potentially before reaching the target deviation." -- | In addition to @--fail-if-slower@ command-line option, -- one can adjust an upper bound of acceptable slow down -- in comparison to baseline for -- individual benchmarks and groups of benchmarks -- using 'adjustOption' and 'localOption'. -- -- E. g., set upper bound of acceptable slow down to 10% as follows: -- -- > localOption (FailIfSlower 0.10) (bgroup [...]) -- newtype FailIfSlower = FailIfSlower Double deriving (Show, Read, Typeable) instance IsOption FailIfSlower where defaultValue = FailIfSlower (1.0 / 0.0) parseValue = fmap FailIfSlower . parsePositivePercents optionName = pure "fail-if-slower" optionHelp = pure "Upper bound of acceptable slow down in percents. If a benchmark is unacceptably slower than baseline (see --baseline), it will be reported as failed." -- | In addition to @--fail-if-faster@ command-line option, -- one can adjust an upper bound of acceptable speed up -- in comparison to baseline for -- individual benchmarks and groups of benchmarks -- using 'adjustOption' and 'localOption'. -- -- E. g., set upper bound of acceptable speed up to 10% as follows: -- -- > localOption (FailIfFaster 0.10) (bgroup [...]) -- newtype FailIfFaster = FailIfFaster Double deriving (Show, Read, Typeable) instance IsOption FailIfFaster where defaultValue = FailIfFaster (1.0 / 0.0) parseValue = fmap FailIfFaster . parsePositivePercents optionName = pure "fail-if-faster" optionHelp = pure "Upper bound of acceptable speed up in percents. If a benchmark is unacceptably faster than baseline (see --baseline), it will be reported as failed." parsePositivePercents :: String -> Maybe Double parsePositivePercents xs = do x <- safeRead xs guard (x > 0) pure (x / 100) -- | Something that can be benchmarked, produced by 'nf', 'whnf', 'nfIO', 'whnfIO', -- 'nfAppIO', 'whnfAppIO' below. -- -- Drop-in replacement for 'Criterion.Benchmarkable' and 'Gauge.Benchmarkable'. -- newtype Benchmarkable = Benchmarkable { _unBenchmarkable :: Int64 -> IO () } deriving (Typeable) showPicos :: Word64 -> String showPicos i | t < 995 = printf "%3.0f ps" t | t < 995e1 = printf "%3.1f ns" (t / 1e3) | t < 995e3 = printf "%3.0f ns" (t / 1e3) | t < 995e4 = printf "%3.1f μs" (t / 1e6) | t < 995e6 = printf "%3.0f μs" (t / 1e6) | t < 995e7 = printf "%3.1f ms" (t / 1e9) | t < 995e9 = printf "%3.0f ms" (t / 1e9) | otherwise = printf "%.1f s" (t / 1e12) where t :: Double t = fromIntegral i showBytes :: Word64 -> String showBytes i | t < 1000 = printf "%3.0f B " t | t < 10189 = printf "%3.1f KB" (t / 1024) | t < 1023488 = printf "%3.0f KB" (t / 1024) | t < 10433332 = printf "%3.1f MB" (t / 1048576) | t < 1048051712 = printf "%3.0f MB" (t / 1048576) | t < 10683731149 = printf "%3.1f GB" (t / 1073741824) | t < 1073204953088 = printf "%3.0f GB" (t / 1073741824) | otherwise = printf "%.1f TB" (t / 1099511627776) where t :: Double t = fromIntegral i -- | It is crucial for precision to make all fields strict and unboxable. data Measurement = Measurement { measTime :: !Word64 -- ^ time in picoseconds , measAllocs :: !Word64 -- ^ allocations in bytes , measCopied :: !Word64 -- ^ copied bytes } deriving (Show, Read) -- | It is crucial for precision to make all fields strict and unboxable. data Estimate = Estimate { estMean :: !Measurement , estSigma :: !Word64 -- ^ stdev in picoseconds } deriving (Show, Read) -- | It is crucial for precision to make all fields strict and unboxable. data Response = Response { respEstimate :: !Estimate , respIfSlower :: !FailIfSlower -- ^ saved value of --fail-if-slower , respIfFaster :: !FailIfFaster -- ^ saved value of --fail-if-faster } deriving (Show, Read) prettyEstimate :: Estimate -> String prettyEstimate (Estimate m sigma) = -- Two sigmas correspond to 95% probability, showPicos (measTime m) ++ " ± " ++ showPicos (2 * sigma) prettyEstimateWithGC :: Estimate -> String prettyEstimateWithGC (Estimate m sigma) = -- Two sigmas correspond to 95% probability, showPicos (measTime m) ++ " ± " ++ showPicos (2 * sigma) ++ ", " ++ showBytes (measAllocs m) ++ " allocated, " ++ showBytes (measCopied m) ++ " copied" csvEstimate :: Estimate -> String csvEstimate (Estimate m sigma) = show (measTime m) ++ "," ++ show (2 * sigma) csvEstimateWithGC :: Estimate -> String csvEstimateWithGC (Estimate m sigma) = show (measTime m) ++ "," ++ show (2 * sigma) ++ "," ++ show (measAllocs m) ++ "," ++ show (measCopied m) predict :: Measurement -- ^ time for one run -> Measurement -- ^ time for two runs -> Estimate predict (Measurement t1 a1 c1) (Measurement t2 a2 c2) = Estimate { estMean = Measurement t a c , estSigma = truncate (sqrt (fromIntegral d) :: Double) } where sqr x = x * x d = sqr (t1 - t) + sqr (t2 - 2 * t) t = (t1 + 2 * t2) `quot` 5 a = (a1 + 2 * a2) `quot` 5 c = (c1 + 2 * c2) `quot` 5 predictPerturbed :: Measurement -> Measurement -> Estimate predictPerturbed t1 t2 = Estimate { estMean = estMean (predict t1 t2) , estSigma = max (estSigma (predict (lo t1) (hi t2))) (estSigma (predict (hi t1) (lo t2))) } where prec = max (fromInteger cpuTimePrecision) 1000000000 -- 1 ms hi meas = meas { measTime = measTime meas + prec } lo meas = meas { measTime = measTime meas - prec } #if !MIN_VERSION_base(4,10,0) getRTSStatsEnabled :: IO Bool #if MIN_VERSION_base(4,6,0) getRTSStatsEnabled = getGCStatsEnabled #else getRTSStatsEnabled = pure False #endif #endif getAllocsAndCopied :: IO (Word64, Word64) getAllocsAndCopied = do enabled <- getRTSStatsEnabled if not enabled then pure (0, 0) else #if MIN_VERSION_base(4,10,0) (\s -> (allocated_bytes s, copied_bytes s)) <$> getRTSStats #elif MIN_VERSION_base(4,6,0) (\s -> (fromIntegral $ bytesAllocated s, fromIntegral $ bytesCopied s)) <$> getGCStats #else pure (0, 0) #endif measureTime :: Int64 -> Benchmarkable -> IO Measurement measureTime n (Benchmarkable act) = do performGC startTime <- fromInteger <$> getCPUTime (startAllocs, startCopied) <- getAllocsAndCopied act n endTime <- fromInteger <$> getCPUTime (endAllocs, endCopied) <- getAllocsAndCopied pure $ Measurement { measTime = endTime - startTime , measAllocs = endAllocs - startAllocs , measCopied = endCopied - startCopied } measureTimeUntil :: Timeout -> RelStDev -> Benchmarkable -> IO Estimate measureTimeUntil timeout (RelStDev targetRelStDev) b = do t1 <- measureTime 1 b go 1 t1 0 where go :: Int64 -> Measurement -> Word64 -> IO Estimate go n t1 sumOfTs = do t2 <- measureTime (2 * n) b let Estimate (Measurement meanN allocN copiedN) sigmaN = predictPerturbed t1 t2 isTimeoutSoon = case timeout of NoTimeout -> False -- multiplying by 1.2 helps to avoid accidental timeouts Timeout micros _ -> (sumOfTs + measTime t1 + 3 * measTime t2) * 12 >= fromInteger micros * 1000000 * 10 isStDevInTargetRange = sigmaN < truncate (max 0 targetRelStDev * fromIntegral meanN) scale = (`quot` fromIntegral n) if isStDevInTargetRange || isTimeoutSoon then pure $ Estimate (Measurement (scale meanN) (scale allocN) (scale copiedN)) (scale sigmaN) else go (2 * n) t2 (sumOfTs + measTime t1) instance IsTest Benchmarkable where testOptions = pure [ Option (Proxy :: Proxy RelStDev) -- FailIfSlower and FailIfFaster must be options of a test provider rather -- than options of an ingredient to allow setting them on per-test level. , Option (Proxy :: Proxy FailIfSlower) , Option (Proxy :: Proxy FailIfFaster) ] run opts b = const $ case getNumThreads (lookupOption opts) of 1 -> do est <- measureTimeUntil (lookupOption opts) (lookupOption opts) b pure $ testPassed $ show (Response est (lookupOption opts) (lookupOption opts)) _ -> pure $ testFailed "Benchmarks should be run in a single-threaded mode (--jobs 1)" -- | Attach a name to 'Benchmarkable'. -- -- This is actually a synonym of 'Test.Tasty.Providers.singleTest' -- to provide an interface compatible with 'Criterion.bench' and 'Gauge.bench'. -- bench :: String -> Benchmarkable -> Benchmark bench = singleTest -- | Attach a name to a group of 'Benchmark'. -- -- This is actually a synonym of 'Test.Tasty.testGroup' -- to provide an interface compatible with 'Criterion.bgroup' -- and 'Gauge.bgroup'. -- bgroup :: String -> [Benchmark] -> Benchmark bgroup = testGroup -- | Benchmarks are actually just a regular 'Test.Tasty.TestTree' in disguise. -- -- This is a drop-in replacement for 'Criterion.Benchmark' and 'Gauge.Benchmark'. -- type Benchmark = TestTree -- | Run benchmarks and report results, providing -- an interface compatible with 'Criterion.defaultMain' -- and 'Gauge.defaultMain'. -- defaultMain :: [Benchmark] -> IO () defaultMain = Test.Tasty.defaultMainWithIngredients benchIngredients . testGroup "All" -- | List of default benchmark ingredients. This is what 'defaultMain' runs. -- benchIngredients :: [Ingredient] benchIngredients = [listingTests, composeReporters consoleBenchReporter csvReporter] funcToBench :: (b -> c) -> (a -> b) -> a -> Benchmarkable funcToBench frc = (Benchmarkable .) . go where go f x n | n <= 0 = pure () | otherwise = do _ <- evaluate (frc (f x)) go f x (n - 1) {-# INLINE funcToBench #-} -- | 'nf' @f@ @x@ measures time to compute -- a normal form (by means of 'rnf') of an application of @f@ to @x@. -- This does not include time to evaluate @f@ or @x@ themselves. -- -- Note that forcing a normal form requires an additional -- traverse of the structure. In certain scenarios (imagine benchmarking 'tail'), -- especially when 'NFData' instance is badly written, -- this traversal may take non-negligible time and affect results. -- -- Drop-in replacement for 'Criterion.nf' and 'Gauge.nf'. -- nf :: NFData b => (a -> b) -> a -> Benchmarkable nf = funcToBench rnf {-# INLINE nf #-} -- | 'whnf' @f@ @x@ measures time to compute -- a weak head normal form of an application of @f@ to @x@. -- This does not include time to evaluate @f@ or @x@ themselves. -- -- Computing only a weak head normal form is -- rarely what intuitively is meant by "evaluation". -- Unless you understand precisely, what is measured, -- it is recommended to use 'nf' instead. -- -- Drop-in replacement for 'Criterion.whnf' and 'Gauge.whnf'. -- whnf :: (a -> b) -> a -> Benchmarkable whnf = funcToBench id {-# INLINE whnf #-} ioToBench :: (b -> c) -> IO b -> Benchmarkable ioToBench frc act = Benchmarkable go where go n | n <= 0 = pure () | otherwise = do val <- act _ <- evaluate (frc val) go (n - 1) {-# INLINE ioToBench #-} -- | 'nfIO' @x@ measures time to evaluate side-effects of @x@ -- and compute its normal form (by means of 'rnf'). -- -- Pure subexpression of an effectful computation @x@ -- may be evaluated only once and get cached; use 'nfAppIO' -- to avoid this. -- -- Note that forcing a normal form requires an additional -- traverse of the structure. In certain scenarios, -- especially when 'NFData' instance is badly written, -- this traversal may take non-negligible time and affect results. -- -- Drop-in replacement for 'Criterion.nfIO' and 'Gauge.nfIO'. -- nfIO :: NFData a => IO a -> Benchmarkable nfIO = ioToBench rnf {-# INLINE nfIO #-} -- | 'whnfIO' @x@ measures time to evaluate side-effects of @x@ -- and compute its weak head normal form. -- -- Pure subexpression of an effectful computation @x@ -- may be evaluated only once and get cached; use 'whnfAppIO' -- to avoid this. -- -- Computing only a weak head normal form is -- rarely what intuitively is meant by "evaluation". -- Unless you understand precisely, what is measured, -- it is recommended to use 'nfIO' instead. -- -- Drop-in replacement for 'Criterion.whnfIO' and 'Gauge.whnfIO'. -- whnfIO :: NFData a => IO a -> Benchmarkable whnfIO = ioToBench id {-# INLINE whnfIO #-} ioFuncToBench :: (b -> c) -> (a -> IO b) -> a -> Benchmarkable ioFuncToBench frc = (Benchmarkable .) . go where go f x n | n <= 0 = pure () | otherwise = do val <- f x _ <- evaluate (frc val) go f x (n - 1) {-# INLINE ioFuncToBench #-} -- | 'nfAppIO' @f@ @x@ measures time to evaluate side-effects of -- an application of @f@ to @x@. -- and compute its normal form (by means of 'rnf'). -- This does not include time to evaluate @f@ or @x@ themselves. -- -- Note that forcing a normal form requires an additional -- traverse of the structure. In certain scenarios, -- especially when 'NFData' instance is badly written, -- this traversal may take non-negligible time and affect results. -- -- Drop-in replacement for 'Criterion.nfAppIO' and 'Gauge.nfAppIO'. -- nfAppIO :: NFData b => (a -> IO b) -> a -> Benchmarkable nfAppIO = ioFuncToBench rnf {-# INLINE nfAppIO #-} -- | 'whnfAppIO' @f@ @x@ measures time to evaluate side-effects of -- an application of @f@ to @x@. -- and compute its weak head normal form. -- This does not include time to evaluate @f@ or @x@ themselves. -- -- Computing only a weak head normal form is -- rarely what intuitively is meant by "evaluation". -- Unless you understand precisely, what is measured, -- it is recommended to use 'nfAppIO' instead. -- -- Drop-in replacement for 'Criterion.whnfAppIO' and 'Gauge.whnfAppIO'. -- whnfAppIO :: (a -> IO b) -> a -> Benchmarkable whnfAppIO = ioFuncToBench id {-# INLINE whnfAppIO #-} -- | Run benchmarks in the given environment, usually reading large input data from file. -- -- One might wonder why 'env' is needed, -- when we can simply read all input data -- before calling 'defaultMain'. The reason is that large data -- dangling in the heap causes longer garbage collection -- and slows down all benchmarks, even those which do not use it at all. -- -- Provided only for the sake of compatibility with 'Criterion.env' and 'Gauge.env', -- and involves 'unsafePerformIO'. Consider using 'withResource' instead. -- env :: NFData env => IO env -> (env -> Benchmark) -> Benchmark env res = envWithCleanup res (const $ pure ()) -- | Similar to 'env', but includes an additional argument -- to clean up created environment. -- -- Provided only for the sake of compatibility -- with 'Criterion.envWithCleanup' and 'Gauge.envWithCleanup', -- and involves 'unsafePerformIO'. Consider using 'withResource' instead. -- envWithCleanup :: NFData env => IO env -> (env -> IO a) -> (env -> Benchmark) -> Benchmark envWithCleanup res fin f = withResource (res >>= evaluate . force) (void . fin) (f . unsafePerformIO) newtype CsvPath = CsvPath { _unCsvPath :: FilePath } deriving (Typeable) instance IsOption (Maybe CsvPath) where defaultValue = Nothing parseValue = Just . Just . CsvPath optionName = pure "csv" optionHelp = pure "File to write results in CSV format" -- | Run benchmarks and save results in CSV format. -- It activates when @--csv@ @FILE@ command line option is specified. -- csvReporter :: Ingredient csvReporter = TestReporter [Option (Proxy :: Proxy (Maybe CsvPath))] $ \opts tree -> do CsvPath path <- lookupOption opts let names = IM.fromDistinctAscList $ zip [0..] (testsNames opts tree) pure $ \smap -> do let augmented = IM.intersectionWith (,) names smap hasGCStats <- getRTSStatsEnabled bracket (do h <- openFile path WriteMode hSetBuffering h LineBuffering hPutStrLn h $ "Name,Mean (ps),2*Stdev (ps)" ++ (if hasGCStats then ",Allocated,Copied" else "") pure h ) hClose (`csvOutput` augmented) pure $ const ((== 0) . statFailures <$> computeStatistics smap) csvOutput :: Handle -> IntMap (TestName, TVar Status) -> IO () csvOutput h = traverse_ $ \(name, tv) -> do hasGCStats <- getRTSStatsEnabled let csv = if hasGCStats then csvEstimateWithGC else csvEstimate r <- atomically $ readTVar tv >>= \s -> case s of Done r -> pure r; _ -> retry case safeRead (resultDescription r) of Nothing -> pure () Just (Response est _ _) -> do msg <- formatMessage $ csv est hPutStrLn h (encodeCsv name ++ ',' : msg) encodeCsv :: String -> String encodeCsv xs | any (`elem` xs) ",\"\n\r" = '"' : concatMap (\x -> if x == '"' then "\"\"" else [x]) xs ++ "\"" | otherwise = xs newtype BaselinePath = BaselinePath { _unBaselinePath :: FilePath } deriving (Typeable) instance IsOption (Maybe BaselinePath) where defaultValue = Nothing parseValue = Just . Just . BaselinePath optionName = pure "baseline" optionHelp = pure "File with baseline results in CSV format to compare against" -- | Run benchmarks and report results -- in a manner similar to 'consoleTestReporter'. -- -- If @--baseline@ @FILE@ command line option is specified, -- compare results against an earlier run and mark -- too slow / too fast benchmarks as failed in accordance to -- bounds specified by @--fail-if-slower@ @PERCENT@ and @--fail-if-faster@ @PERCENT@. -- consoleBenchReporter :: Ingredient consoleBenchReporter = modifyConsoleReporter [Option (Proxy :: Proxy (Maybe BaselinePath))] $ \opts -> do baseline <- case lookupOption opts of Nothing -> pure S.empty Just (BaselinePath path) -> S.fromList . lines <$> (readFile path >>= evaluate . force) hasGCStats <- getRTSStatsEnabled let pretty = if hasGCStats then prettyEstimateWithGC else prettyEstimate pure $ \name r -> case safeRead (resultDescription r) of Nothing -> r Just (Response est (FailIfSlower ifSlow) (FailIfFaster ifFast)) -> (if isAcceptable then id else forceFail) r { resultDescription = pretty est ++ formatSlowDown slowDown } where slowDown = compareVsBaseline baseline name est isAcceptable -- ifSlow/ifFast may be infinite, so we cannot 'truncate' = fromIntegral slowDown <= 100 * ifSlow && fromIntegral slowDown >= -100 * ifFast compareVsBaseline :: S.Set TestName -> TestName -> Estimate -> Int64 compareVsBaseline baseline name (Estimate m sigma) = case mOld of Nothing -> 0 Just (oldTime, oldDoubleSigma) | abs (time - oldTime) < max (2 * fromIntegral sigma) oldDoubleSigma -> 0 | otherwise -> 100 * (time - oldTime) `quot` oldTime where time = fromIntegral $ measTime m mOld = do let prefix = encodeCsv name ++ "," line <- lookupGE prefix baseline (timeCell, ',' : rest) <- span (/= ',') <$> stripPrefix prefix line let doubleSigmaCell = takeWhile (/= ',') rest (,) <$> safeRead timeCell <*> safeRead doubleSigmaCell formatSlowDown :: Int64 -> String formatSlowDown n = case n `compare` 0 of LT -> printf ", %2i%% faster than baseline" (-n) EQ -> "" GT -> printf ", %2i%% slower than baseline" n forceFail :: Result -> Result forceFail r = r { resultOutcome = Failure TestFailed, resultShortDescription = "FAIL" } #if !MIN_VERSION_containers(0,5,0) lookupGE :: TestName -> S.Set TestName -> Maybe TestName lookupGE x = fmap fst . S.minView . S.filter (x `isPrefixOf`) #endif modifyConsoleReporter :: [OptionDescription] -> (OptionSet -> IO (TestName -> Result -> Result)) -> Ingredient modifyConsoleReporter desc' iof = TestReporter (desc ++ desc') $ \opts tree -> let names = IM.fromDistinctAscList $ zip [0..] (testsNames opts tree) modifySMap = (iof opts >>=) . flip postprocessResult . IM.intersectionWith (,) names in (modifySMap >=>) <$> cb opts tree where TestReporter desc cb = consoleTestReporter postprocessResult :: (TestName -> Result -> Result) -> IntMap (TestName, TVar Status) -> IO StatusMap postprocessResult f src = do paired <- forM src $ \(name, tv) -> (name, tv,) <$> newTVarIO NotStarted let doUpdate = atomically $ do (Any anyUpdated, All allDone) <- getApp $ flip foldMap paired $ \(name, newTV, oldTV) -> Ap $ do old <- readTVar oldTV case old of Done{} -> pure (Any False, All True) _ -> do new <- readTVar newTV case new of Done res -> do writeTVar oldTV (Done (f name res)) pure (Any True, All True) -- ignoring Progress nodes, we do not report any -- it would be helpful to have instance Eq Status _ -> pure (Any False, All False) if anyUpdated || allDone then pure allDone else retry adNauseam = doUpdate >>= (`unless` adNauseam) _ <- forkIO adNauseam pure $ fmap (\(_, _, a) -> a) paired