From e07c4ffc395d83bbae3f440b372593a068fb02df Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Thu, 23 Apr 2020 21:48:30 +0200
Subject: [PATCH] stream: fix sync write perf regression

While https://github.com/nodejs/node/pull/31046 did make async
writes faster it at the same time made sync writes slower.

This PR corrects this while maintaining performance improvements.

PR-URL: https://github.com/nodejs/node/pull/33032
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Zeyu Yang <himself65@outlook.com>
---
 lib/_stream_writable.js | 31 ++++++++++++++-----------------
 1 file changed, 14 insertions(+), 17 deletions(-)

diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index 2dc949316a2dce..4b353a52665efa 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -415,27 +415,24 @@ function onwrite(stream, er) {
       onwriteError(stream, state, er, cb);
     }
   } else {
-    if (!state.destroyed) {
+    if (state.buffered.length > state.bufferedIndex) {
       clearBuffer(stream, state);
     }
-    if (state.needDrain || cb !== nop || state.ending || state.destroyed) {
-      if (sync) {
-        // It is a common case that the callback passed to .write() is always
-        // the same. In that case, we do not schedule a new nextTick(), but
-        // rather just increase a counter, to improve performance and avoid
-        // memory allocations.
-        if (state.afterWriteTickInfo !== null &&
-            state.afterWriteTickInfo.cb === cb) {
-          state.afterWriteTickInfo.count++;
-        } else {
-          state.afterWriteTickInfo = { count: 1, cb, stream, state };
-          process.nextTick(afterWriteTick, state.afterWriteTickInfo);
-        }
+
+    if (sync) {
+      // It is a common case that the callback passed to .write() is always
+      // the same. In that case, we do not schedule a new nextTick(), but
+      // rather just increase a counter, to improve performance and avoid
+      // memory allocations.
+      if (state.afterWriteTickInfo !== null &&
+          state.afterWriteTickInfo.cb === cb) {
+        state.afterWriteTickInfo.count++;
       } else {
-        afterWrite(stream, state, 1, cb);
+        state.afterWriteTickInfo = { count: 1, cb, stream, state };
+        process.nextTick(afterWriteTick, state.afterWriteTickInfo);
       }
     } else {
-      state.pendingcb--;
+      afterWrite(stream, state, 1, cb);
     }
   }
 }
@@ -483,7 +480,7 @@ function errorBuffer(state, err) {
 
 // If there's something in the buffer waiting, then process it.
 function clearBuffer(stream, state) {
-  if (state.corked || state.bufferProcessing) {
+  if (state.corked || state.bufferProcessing || state.destroyed) {
     return;
   }