calling threadWaitWrite only when errnor is eAGAIN

kazu-yamamoto · Nov 21, 2012 · 2b09a9b · 2b09a9b
1 parent 8771596
commit 2b09a9b
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/Network/Sendfile/BSD.hsc b/Network/Sendfile/BSD.hsc
@@ -74,7 +74,9 @@ sendloop dst src off len sentp hook = do
         if errno `elem` [eAGAIN, eINTR] then do
             sent <- peek sentp
             hook
-            threadWaitWrite dst
+            -- Parallel IO manager use edge-trigger mode.
+            -- So, calling threadWaitWrite only when errnor is eAGAIN.
+            when (errno == eAGAIN) $ threadWaitWrite dst
             let newoff = off + sent
                 newlen = if len == entire then entire else len - sent
             sendloop dst src newoff newlen sentp hook
@@ -163,7 +165,9 @@ sendloopHeader dst src off len sentp hdr hlen = do
                   else
                     return $ Just (newoff, len - sent)
               else do
-                threadWaitWrite dst
+                -- Parallel IO manager use edge-trigger mode.
+                -- So, calling threadWaitWrite only when errnor is eAGAIN.
+                when (errno == eAGAIN) $ threadWaitWrite dst
                 let newlen = if len == entire then entire else len - sent
                     newhdr = remainingChunks (fromIntegral sent) hdr
                     newhlen = hlen - sent

diff --git a/Network/Sendfile/Linux.hsc b/Network/Sendfile/Linux.hsc
@@ -102,7 +102,9 @@ sendloop dst src offp len hook = do
     loop 0    = return ()
     loop left = do
         hook
-        threadWaitWrite dst
+        -- Parallel IO manager use edge-trigger mode.
+        -- So, calling threadWaitWrite only when errnor is eAGAIN.
+        when (errno == eAGAIN) $ threadWaitWrite dst
         sendloop dst src offp left hook
 
 -- Dst Src in order. take care