refactor(sut): shuffle worker loop around a bit

doc/demo-journal/slides-journal.md

@@ -223,6 +223,9 @@ done
 # Disable turbo boost.
 echo 1 | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo
 
+# Allow for more open file descriptors.
+ulimit -n unlimited
+
 # The following run is just a (CPU) warm up, the results are discarded.
 cabal run bench-sqlite
 

src/sut/dumblog/bench/Common.hs

@@ -42,7 +42,7 @@ rEAD_FREQUENCY :: Int
 rEAD_FREQUENCY = 80
 
 iTERATIONS :: Int
-iTERATIONS = 50000
+iTERATIONS = 100000
 
 vALUE_TO_WRITE :: ByteString
 vALUE_TO_WRITE = LBS.pack "Dumblog"

src/sut/dumblog/src/Dumblog/Journal/Worker.hs

@@ -47,18 +47,20 @@ worker :: Journal -> DumblogMetrics -> WorkerInfo -> InMemoryDumblog -> IO ()
 worker journal metrics (WorkerInfo blocker logger snapshotFile currentVersion eventCount untilSnapshot) =
   go eventCount
   where
-    go ev s
-      | ev >= untilSnapshot = do
-          logger "[worker] Performing Snapshot"
-          bytes <- readBytesConsumed (jMetadata journal) Sub1
-          Snapshot.toFile (Snapshot.Snapshot bytes currentVersion s) snapshotFile
-          writeBytesConsumed (jMetadata journal) Sub2 bytes
-          go 0 s
+    go :: Int -> InMemoryDumblog -> IO ()
     go ev s = do
-      { val <- Journal.readJournal journal Sub1
-      ; (ev', s') <- case val of
-        { Nothing -> return (ev, s)
-        ; Just entry -> do
+      if ev >= untilSnapshot
+      then do
+        logger "[worker] Performing Snapshot"
+        bytes <- readBytesConsumed (jMetadata journal) Sub1
+        Snapshot.toFile (Snapshot.Snapshot bytes currentVersion s) snapshotFile
+        writeBytesConsumed (jMetadata journal) Sub2 bytes
+        go 0 s
+      else do
+        mEntry <- Journal.readJournal journal Sub1
+        case mEntry of
+          Nothing -> threadDelay 0 >> go ev s
+          Just entry -> do
             Metrics.decrCounter_ metrics QueueDepth 1
             let Envelope key cmd version arrivalTime = decode entry
             -- XXX: In case of decode error:
@@ -81,9 +83,4 @@ worker journal metrics (WorkerInfo blocker logger snapshotFile currentVersion ev
             case cmd of
               Write bs   -> Metrics.measure metrics WriteSize (realToFrac (BS.length bs))
               _otherwise -> return ()
-            return (succ ev, s')
-
-        }
-      ; threadDelay 10
-      ; go ev' s'
-      }
+            go (ev + 1) s'

src/sut/dumblog/tools/benchmark-run.sh

@@ -28,6 +28,9 @@ cabal build "${BENCHMARK_CABAL_BUILD_OPTS[@]}" "${BENCHMARK_WORKLOAD2}"
 # Disable turbo boost.
 echo 1 | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo
 
+# Allow for more open file descriptors.
+ulimit -n unlimited
+
 # The following run is just a (CPU) warm up, the results are discarded.
 cabal run "${BENCHMARK_CABAL_RUN_OPTS[@]}" "${BENCHMARK_WORKLOAD2}"