From f283df5497e0d4387911359a529fafa979a7bb14 Mon Sep 17 00:00:00 2001
From: Nitzan Uziely <linkgoron@gmail.com>
Date: Fri, 5 Mar 2021 14:37:57 +0200
Subject: [PATCH] fs: improve fsPromises writeFile performance

Increase the write chunk size in fsPromises writeFile
to improve performance.

PR-URL: https://github.com/nodejs/node/pull/37610
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
---
 lib/internal/fs/promises.js                             | 4 +++-
 lib/internal/fs/utils.js                                | 5 +++++
 test/parallel/test-fs-promises-file-handle-writeFile.js | 2 +-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/internal/fs/promises.js b/lib/internal/fs/promises.js
index 39418446bd9c15..16efc1c6398abb 100644
--- a/lib/internal/fs/promises.js
+++ b/lib/internal/fs/promises.js
@@ -7,7 +7,6 @@ const kIoMaxLength = 2 ** 31 - 1;
 // Note: This is different from kReadFileBufferLength used for non-promisified
 // fs.readFile.
 const kReadFileMaxChunkSize = 2 ** 14;
-const kWriteFileMaxChunkSize = 2 ** 14;
 
 // 2 ** 32 - 1
 const kMaxUserId = 4294967295;
@@ -44,6 +43,9 @@ const {
 const { isArrayBufferView } = require('internal/util/types');
 const { rimrafPromises } = require('internal/fs/rimraf');
 const {
+  constants: {
+    kWriteFileMaxChunkSize
+  },
   copyObject,
   getDirents,
   getOptions,
diff --git a/lib/internal/fs/utils.js b/lib/internal/fs/utils.js
index d3f4c621e4dd56..6f30d1b020da9f 100644
--- a/lib/internal/fs/utils.js
+++ b/lib/internal/fs/utils.js
@@ -113,6 +113,8 @@ const kMaximumCopyMode = COPYFILE_EXCL |
                          COPYFILE_FICLONE |
                          COPYFILE_FICLONE_FORCE;
 
+const kWriteFileMaxChunkSize = 512 * 1024;
+
 const isWindows = process.platform === 'win32';
 
 let fs;
@@ -815,6 +817,9 @@ const validatePosition = hideStackFrames((position, name) => {
 });
 
 module.exports = {
+  constants: {
+    kWriteFileMaxChunkSize
+  },
   assertEncoding,
   BigIntStats,  // for testing
   copyObject,
diff --git a/test/parallel/test-fs-promises-file-handle-writeFile.js b/test/parallel/test-fs-promises-file-handle-writeFile.js
index a4ae7fd054b53d..3f5e9a20c4d470 100644
--- a/test/parallel/test-fs-promises-file-handle-writeFile.js
+++ b/test/parallel/test-fs-promises-file-handle-writeFile.js
@@ -31,7 +31,7 @@ async function validateWriteFile() {
 async function doWriteAndCancel() {
   const filePathForHandle = path.resolve(tmpDir, 'dogs-running.txt');
   const fileHandle = await open(filePathForHandle, 'w+');
-  const buffer = Buffer.from('dogs running'.repeat(10000), 'utf8');
+  const buffer = Buffer.from('dogs running'.repeat(512 * 1024), 'utf8');
   const controller = new AbortController();
   const { signal } = controller;
   process.nextTick(() => controller.abort());