fs: improve fsPromises writeFile performance

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

PR-URL: nodejs#37610
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Darshan Sen <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Antoine du Hamel <[email protected]>

Author: Linkgoron

lib/internal/fs/promises.js

@@ -4,10 +4,8 @@
 // See https://github.com./libuv/libuv/pull/1501.
 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;
+const kReadFileBufferLength = 512 * 1024;
+const kReadFileUnknownBufferLength = 64 * 1024;
 
 // 2 ** 32 - 1
 const kMaxUserId = 4294967295;
@@ -44,6 +42,9 @@ const {
 const { isArrayBufferView } = require('internal/util/types');
 const { rimrafPromises } = require('internal/fs/rimraf');
 const {
+  constants: {
+    kWriteFileMaxChunkSize
+  },
   copyObject,
   getDirents,
   getOptions,

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,

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());