Hi there! I'm currently trying to write a program for the creation of IQ samples from various sound files; AM is my current focus. This seems like a really good application for the conduit library. I've so far got: --8<---------------cut here---------------start------------->8--- run :: AMOptions -> IO () run opts = do (info, Just (aSamps :: SV.Buffer Float)) <- SF.readFile $ inputFile opts putStr "Processing samples... " hFlush stdout runConduitRes $ yieldMany (SV.fromBuffer aSamps) .| modulateAM (modIndex opts) .| zeroStuff (upsample opts) .| mapC renderSample .| unsafeBuilderToByteString .| sinkFile (outputFile opts) --8<---------------cut here---------------end--------------->8--- However, this is *slow*. It takes over 40 seconds to run; I've previously implemented the above without using streaming and this code took approx 3 seconds to run with the same input. I compiled the code for profiling and it appears as though the main culprit is the function `injectLeftovers': --8<---------------cut here---------------start------------->8--- Mon Jun 28 22:55 2021 Time and Allocation Profiling Report (Final) ayeQ +RTS -p -RTS am -i /Users/matthew/40.flac -o /Users/matthew/out.cfile -u 15 -m 150 total time = 76.32 secs (76322 ticks @ 1000 us, 1 processor) total alloc = 445,275,685,456 bytes (excludes profiling overheads) COST CENTRE MODULE SRC %time %alloc injectLeftovers Data.Conduit.Internal.Pipe src/Data/Conduit/Internal/Pipe.hs:(410,1)-(418,38) 79.5 81.6 runPipe Data.Conduit.Internal.Pipe src/Data/Conduit/Internal/Pipe.hs:(395,1)-(399,33) 7.1 5.0 awaitForever Data.Conduit.Internal.Conduit src/Data/Conduit/Internal/Conduit.hs:(950,1)-(952,10) 5.3 3.7 run AM AM.hs:(62,1)-(77,88) 4.4 7.0 renderSample Render Render.hs:8:1-58 3.5 2.5 --8<---------------cut here---------------end--------------->8--- I'm at a bit of a loss as to where to start looking for why this particlar function is using so many resources, or which part of the pipeline is causing the issue. The custom pieces of code that I've got in the pipeline are: --8<---------------cut here---------------start------------->8--- modulateAM' :: Int -> Float -> IQ modulateAM' modIdx s = (base + amp) :+ 0.0 where x = fromIntegral modIdx / 200 amp = s * x base = 1 - x modulateAM :: Monad m => Int -> ConduitT Float IQ m () modulateAM = mapC . modulateAM' --8<---------------cut here---------------end--------------->8--- --8<---------------cut here---------------start------------->8--- zeroStuff :: Monad m => Int -> ConduitT IQ IQ m () zeroStuff factor = awaitForever (\v -> yield v >> replicateM_ (factor - 1) (yield zero)) where zero = 0 :+ 0 --8<---------------cut here---------------end--------------->8--- --8<---------------cut here---------------start------------->8--- renderSample :: IQ -> Builder renderSample (real :+ imag) = floatLE real <> floatLE imag --8<---------------cut here---------------end--------------->8--- Any help would be appreciated! Regards, -- Matt