fs: improve writevSync performance

Author: ilyasShabiCS

benchmark/fs/bench-writevSync.js

@@ -0,0 +1,40 @@
+'use strict';
+
+const common = require('../common');
+const fs = require('fs');
+const tmpdir = require('../../test/common/tmpdir');
+tmpdir.refresh();
+
+const path = tmpdir.resolve(`new-file-${process.pid}`);
+fs.writeFileSync(path, 'Some content.');
+
+const bench = common.createBenchmark(main, {
+  type: ['valid'],
+  n: [1e5],
+});
+
+const buffer = Buffer.from('Benchmark data.');
+
+function main({ n, type }) {
+  let fd;
+
+  switch (type) {
+    case 'valid':
+      fd = fs.openSync(path, 'r+');
+      break;
+    default:
+      throw new Error('Invalid type');
+  }
+
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    try {
+      fs.writevSync(fd, [buffer]);
+    } catch {
+      // do nothing
+    }
+  }
+  bench.end(n);
+
+  if (type === 'valid') fs.closeSync(fd);
+}

lib/fs.js

@@ -998,12 +998,10 @@ function writevSync(fd, buffers, position) {
     return 0;
   }
 
-  const ctx = {};
-
   if (typeof position !== 'number')
     position = null;
 
-  const result = binding.writeBuffers(fd, buffers, position, undefined, ctx);
+  const result = binding.writeBuffers(fd, buffers, position);
 
   handleErrorFromBinding(ctx);
   return result;

src/node_file.cc

@@ -2205,18 +2205,21 @@ static void WriteBuffers(const FunctionCallbackInfo<Value>& args) {
     iovs[i] = uv_buf_init(Buffer::Data(chunk), Buffer::Length(chunk));
   }
 
-  FSReqBase* req_wrap_async = GetReqWrap(args, 3);
-  if (req_wrap_async != nullptr) {  // writeBuffers(fd, chunks, pos, req)
-    FS_ASYNC_TRACE_BEGIN0(UV_FS_WRITE, req_wrap_async)
-    AsyncCall(env, req_wrap_async, args, "write", UTF8, AfterInteger,
+  if(argc > 3) {
+      FSReqBase* req_wrap_async = GetReqWrap(args, 3);
+      FS_ASYNC_TRACE_BEGIN0(UV_FS_WRITE, req_wrap_async)
+      AsyncCall(env, req_wrap_async, args, "write", UTF8, AfterInteger,
               uv_fs_write, fd, *iovs, iovs.length(), pos);
-  } else {  // writeBuffers(fd, chunks, pos, undefined, ctx)
-    CHECK_EQ(argc, 5);
+  } else {
     FSReqWrapSync req_wrap_sync;
     FS_SYNC_TRACE_BEGIN(write);
-    int bytesWritten = SyncCall(env, args[4], &req_wrap_sync, "write",
+    int bytesWritten = SyncCallAndThrowOnError(env, &req_wrap_sync,
                                 uv_fs_write, fd, *iovs, iovs.length(), pos);
     FS_SYNC_TRACE_END(write, "bytesWritten", bytesWritten);
+    
+     if (is_uv_error(bytesWritten)) {
+      return;
+    }
     args.GetReturnValue().Set(bytesWritten);
   }
 }