diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # lzlib
 
+## 0.3.0.1
+
+  * Performance improvements
+
 ## 0.3.0.0
 
   * Take a `BSL.ByteString` as input
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -6,12 +6,23 @@
 
 Haskell bindings to [lzlib](https://www.nongnu.org/lzip/lzlib.html).
 
+This package includes a high-level interface to lzlib, however, it is slow.
+
 ## Hacking
 
 Run
 
 ```bash
-./bash/setup
+make -j
 ```
 
 to download a few tarballs before running the test suite.
+
+### CI
+
+To edit the CI script, edit `haskell-ci.dhall` and regenerate
+`.github/workflows/haskell.yml` with
+
+```
+make ci
+```
diff --git a/bench/Bench.hs b/bench/Bench.hs
--- a/bench/Bench.hs
+++ b/bench/Bench.hs
@@ -31,9 +31,11 @@
                       ]
                 , bgroup "unpack"
                       [ bench "lzlib" $ nfIO unpack ]
-                , env decompressed $ \f ->
+                , env decompressedFiles $ \ ~(f, g) ->
                   bgroup "roundtrip'"
-                      [ bench "lzlib" $ nf roundtrip' f ]
+                      [ bench "lzlib (lzlib)" $ nf roundtrip' f
+                      , bench "lzlib (gmp)" $ nf roundtrip' g
+                      ]
                 , bgroup "unpack"
                       [ bench "lzlib" $ nfIO unpack' ]
                 ]
@@ -41,3 +43,5 @@
           bigFile = BSL.readFile "gmp-6.1.2.tar.lz"
           files = (,) <$> file <*> bigFile
           decompressed = BSL.readFile "lzlib-1.10.tar"
+          bigDecompressed = BSL.readFile "gmp-6.1.2.tar"
+          decompressedFiles = (,) <$> decompressed <*> bigDecompressed
diff --git a/lzlib.cabal b/lzlib.cabal
--- a/lzlib.cabal
+++ b/lzlib.cabal
@@ -1,6 +1,6 @@
 cabal-version:      1.18
 name:               lzlib
-version:            0.3.0.0
+version:            0.3.0.1
 license:            BSD3
 license-file:       LICENSE
 copyright:          Copyright: (c) 2019 Vanessa McHale
@@ -45,7 +45,7 @@
         Codec.Lzip
         Codec.Lzip.Raw
 
-    cc-options:       -O1
+    cc-options:       -O3
     c-sources:        cbits/lzlib.c
     hs-source-dirs:   src
     default-language: Haskell2010
diff --git a/src/Codec/Lzip.hs b/src/Codec/Lzip.hs
--- a/src/Codec/Lzip.hs
+++ b/src/Codec/Lzip.hs
@@ -58,6 +58,8 @@
     maxSz <- lZDecompressWriteSize decoder
 
     let bss = BSL.toChunks bs
+        -- TODO: this might be silly: does it force everything into memory
+        -- prematurely?
         sz = maximum (BS.length <$> bss)
         bufMax = fromIntegral maxSz
 
@@ -73,7 +75,7 @@
         loop :: LZDecoderPtr -> [BS.ByteString] -> Int -> (Ptr UInt8, Int) -> [BS.ByteString] -> IO [BS.ByteString]
         loop decoder bss maxSz (buf, bufSz) !acc = do
             bss' <- case bss of
-                [bs'] -> if BS.length bs' > maxSz 
+                [bs'] -> if BS.length bs' > maxSz
                     then do
                         let (bs'', rest) = BS.splitAt maxSz bs'
                         BS.useAsCStringLen bs'' $ \(bytes, sz) ->
diff --git a/stack.yaml b/stack.yaml
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,5 +1,5 @@
 ---
-resolver: lts-14.7
+resolver: lts-14.16
 ghc-options: {"$locals": -ddump-to-file -ddump-hi}
 packages:
   - '.'