diff --git a/lib/internal/fs/promises.js b/lib/internal/fs/promises.js
index 39418446bd9c15..696c904be35c7f 100644
--- a/lib/internal/fs/promises.js
+++ b/lib/internal/fs/promises.js
@@ -1,18 +1,7 @@
 'use strict';
 
-// Most platforms don't allow reads or writes >= 2 GB.
-// 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;
-
-// 2 ** 32 - 1
-const kMaxUserId = 4294967295;
-
 const {
+  ArrayPrototypePush,
   Error,
   MathMax,
   MathMin,
@@ -44,6 +33,13 @@ const {
 const { isArrayBufferView } = require('internal/util/types');
 const { rimrafPromises } = require('internal/fs/rimraf');
 const {
+  constants: {
+    kIoMaxLength,
+    kMaxUserId,
+    kReadFileBufferLength,
+    kReadFileUnknownBufferLength,
+    kWriteFileMaxChunkSize,
+  },
   copyObject,
   getDirents,
   getOptions,
@@ -296,24 +292,46 @@ async function readFileHandle(filehandle, options) {
   if (size > kIoMaxLength)
     throw new ERR_FS_FILE_TOO_LARGE(size);
 
-  const chunks = [];
-  const chunkSize = size === 0 ?
-    kReadFileMaxChunkSize :
-    MathMin(size, kReadFileMaxChunkSize);
   let endOfFile = false;
+  let totalRead = 0;
+  const noSize = size === 0;
+  const buffers = [];
+  const fullBuffer = noSize ? undefined : Buffer.allocUnsafeSlow(size);
   do {
     if (signal && signal.aborted) {
       throw lazyDOMException('The operation was aborted', 'AbortError');
     }
-    const buf = Buffer.alloc(chunkSize);
-    const { bytesRead, buffer } =
-      await read(filehandle, buf, 0, chunkSize, -1);
-    endOfFile = bytesRead === 0;
-    if (bytesRead > 0)
-      chunks.push(buffer.slice(0, bytesRead));
+    let buffer;
+    let offset;
+    let length;
+    if (noSize) {
+      buffer = Buffer.allocUnsafeSlow(kReadFileUnknownBufferLength);
+      offset = 0;
+      length = kReadFileUnknownBufferLength;
+    } else {
+      buffer = fullBuffer;
+      offset = totalRead;
+      length = MathMin(size - totalRead, kReadFileBufferLength);
+    }
+
+    const bytesRead = (await binding.read(filehandle.fd, buffer, offset,
+                                          length, -1, kUsePromises)) || 0;
+    totalRead += bytesRead;
+    endOfFile = bytesRead === 0 || totalRead === size;
+    if (noSize && bytesRead > 0) {
+      const isBufferFull = bytesRead === kReadFileUnknownBufferLength;
+      const chunkBuffer = isBufferFull ? buffer : buffer.slice(0, bytesRead);
+      ArrayPrototypePush(buffers, chunkBuffer);
+    }
   } while (!endOfFile);
 
-  const result = chunks.length === 1 ? chunks[0] : Buffer.concat(chunks);
+  let result;
+  if (size > 0) {
+    result = totalRead === size ? fullBuffer : fullBuffer.slice(0, totalRead);
+  } else {
+    result = buffers.length === 1 ? buffers[0] : Buffer.concat(buffers,
+                                                               totalRead);
+  }
 
   return options.encoding ? result.toString(options.encoding) : result;
 }
diff --git a/lib/internal/fs/utils.js b/lib/internal/fs/utils.js
index d3f4c621e4dd56..6af79033f452b6 100644
--- a/lib/internal/fs/utils.js
+++ b/lib/internal/fs/utils.js
@@ -113,6 +113,23 @@ const kMaximumCopyMode = COPYFILE_EXCL |
                          COPYFILE_FICLONE |
                          COPYFILE_FICLONE_FORCE;
 
+// Most platforms don't allow reads or writes >= 2 GB.
+// See https://github.com/libuv/libuv/pull/1501.
+const kIoMaxLength = 2 ** 31 - 1;
+
+// Use 64kb in case the file type is not a regular file and thus do not know the
+// actual file size. Increasing the value further results in more frequent over
+// allocation for small files and consumes CPU time and memory that should be
+// used else wise.
+// Use up to 512kb per read otherwise to partition reading big files to prevent
+// blocking other threads in case the available threads are all in use.
+const kReadFileUnknownBufferLength = 64 * 1024;
+const kReadFileBufferLength = 512 * 1024;
+
+const kWriteFileMaxChunkSize = 512 * 1024;
+
+const kMaxUserId = 2 ** 32 - 1;
+
 const isWindows = process.platform === 'win32';
 
 let fs;
@@ -815,6 +832,13 @@ const validatePosition = hideStackFrames((position, name) => {
 });
 
 module.exports = {
+  constants: {
+    kIoMaxLength,
+    kMaxUserId,
+    kReadFileBufferLength,
+    kReadFileUnknownBufferLength,
+    kWriteFileMaxChunkSize,
+  },
   assertEncoding,
   BigIntStats,  // for testing
   copyObject,