49542d2 · streamly · git.iko.soy

Changelog.md+8

compare with master

unifiedsplit

@@ -1,3 +1,11 @@

1+## Unreleased

2+

3+### Bug Fixes

4+

5+* Fixed a livelock in ahead style streams. The problem manifests sometimes when

6+ multiple streams are merged together in ahead style and one of them is a nil

7+ stream.

8+

1## 0.5.1

9## 0.5.1

2

10

3* Performance improvements, especially space consumption, for concurrent

11* Performance improvements, especially space consumption, for concurrent

src/Streamly/SVar.hs+2−1

@@ -189,7 +189,8 @@ data ChildEvent a =

189

190-- | Sorting out-of-turn outputs in a heap for Ahead style streams

191data AheadHeapEntry (t :: (* -> *) -> * -> *) m a =

192+ AheadEntryNull

192− AheadEntryPure a

193+ | AheadEntryPure a

193 | AheadEntryStream (t m a)

194 | AheadEntryStream (t m a)

194

195

195------------------------------------------------------------------------------

196------------------------------------------------------------------------------

src/Streamly/Streams/Ahead.hs+7−1

@@ -230,6 +230,7 @@ processHeap q heap st sv winfo entry sno stopping = loopHeap sno entry

230

231 loopHeap seqNo ent =

232 case ent of

233+ AheadEntryNull -> nextHeap seqNo

233 AheadEntryPure a -> do

234 AheadEntryPure a -> do

234 -- Use 'send' directly so that we do not account this in worker

235 -- Use 'send' directly so that we do not account this in worker

235 -- latency as this will not be the real latency.

236 -- latency as this will not be the real latency.

@@ -338,7 +339,12 @@ processWithoutToken q heap st sv winfo m sno = do

338 -- we have already decremented the yield limit for m

339 -- we have already decremented the yield limit for m

339 let stop = do

340 let stop = do

340 liftIO (incrementYieldLimit sv)

341 liftIO (incrementYieldLimit sv)

341− workLoopAhead q heap st sv winfo

342+ -- If the stream stops without yielding anything, and we do not put

343+ -- anything on heap, but if heap was waiting for this seq number

344+ -- then it will keep waiting forever, because we are never going to

345+ -- put it on heap. So we have to put a null entry on heap even when

346+ -- we stop.

347+ toHeap sno AheadEntryNull

342

348

343 unStream m st stop (singleToHeap sno) (yieldToHeap sno)

349 unStream m st stop (singleToHeap sno) (yieldToHeap sno)

344

350