Make the C benchmark fairer, by not specialising c or d

bos · Sep 30, 2012 · 9227325 · 9227325
1 parent 881b0e0
commit 9227325
Show file tree

Hide file tree

Showing 2 changed files with 24 additions and 8 deletions.
diff --git a/benchmarks/Benchmarks.hs b/benchmarks/Benchmarks.hs
@@ -11,7 +11,7 @@ import Foreign.ForeignPtr
 import GHC.Exts
 import GHC.ST (ST(..))
 import Data.Word
-import Foreign.C.Types (CSize(..))
+import Foreign.C.Types (CInt(..), CSize(..))
 import Foreign.Ptr
 import Data.ByteString.Internal
 import qualified Data.ByteString as B
@@ -54,7 +54,7 @@ main = do
         hsSipHash = HS.hash (HS.SipKey k0 k1)
         cSipHash (PS fp off len) =
             inlinePerformIO . withForeignPtr fp $ \ptr ->
-            return $! c_siphash k0 k1 (ptr `plusPtr` off) (fromIntegral len)
+            return $! c_siphash 2 4 k0 k1 (ptr `plusPtr` off) (fromIntegral len)
 
     withForeignPtr fp5 $ \ p5 ->
         withForeignPtr fp8 $ \ p8 ->
@@ -131,4 +131,4 @@ new (I# n#) = unBA (runST $ ST $ \s1 ->
             (# s3, ba #) -> (# s3, BA ba #))
 
 foreign import ccall unsafe "siphash" c_siphash
-    :: Word64 -> Word64 -> Ptr Word8 -> CSize -> Word64
+    :: CInt -> CInt -> Word64 -> Word64 -> Ptr Word8 -> CSize -> Word64
diff --git a/benchmarks/cbits/siphash.c b/benchmarks/cbits/siphash.c
@@ -14,20 +14,26 @@ typedef uint8_t u8;
     v2 += v1; v1=ROTL(v1,17); v1 ^= v2; v2=ROTL(v2,32); \
   } while(0)
 
-u64 siphash(u64 k0, u64 k1, const u8 *str, size_t len)
+u64 siphash(int c, int d, u64 k0, u64 k1, const u8 *str, size_t len)
 {
     u64 v0 = 0x736f6d6570736575ull ^ k0;
     u64 v1 = 0x646f72616e646f6dull ^ k1;
     u64 v2 = 0x6c7967656e657261ull ^ k0;
     u64 v3 = 0x7465646279746573ull ^ k1;
     u64 b = ((u64) len) << 56;
     const u8 *end, *p;
+    int i;
 
     for (p = str, end = str + (len & ~7); p < end; p += 8) {
 	u64 m = *(u64 *) p;
 	v3 ^= m;
-	SIPROUND;
-	SIPROUND;
+	if (c == 2) {
+	    SIPROUND;
+	    SIPROUND;
+	} else {
+	    for (i = 0; i < c; i++)
+		SIPROUND;
+	}
 	v0 ^= m;
     }
 
@@ -42,15 +48,25 @@ u64 siphash(u64 k0, u64 k1, const u8 *str, size_t len)
     }
 
     v3 ^= b;
-    SIPROUND;
-    SIPROUND;
+    if (c == 2) {
+	SIPROUND;
+	SIPROUND;
+    } else {
+	for (i = 0; i < c; i++)
+	    SIPROUND;
+    }
     v0 ^= b;
 
     v2 ^= 0xff;
+    if (d == 4) {
     SIPROUND;
     SIPROUND;
     SIPROUND;
     SIPROUND;
+    } else {
+	for (i = 0; i < d; i++)
+	    SIPROUND;
+    }
     b = v0 ^ v1 ^ v2  ^ v3;
     return b;
 }