Skip to content

Reduce syscalls on require()

Rodrigo Muino Tomonari requested to merge github/fork/pierreinglebert/require-reduce-syscalls into master

In some conditions, require makes many useless syscalls trying to find files in non-existent directories.

For example, this is a require('moment'); in one subfolder of my project, the lib/sub/node_modules doesn't even exist.

stat64("/Users/pierre/Projects/require_test/lib/sub/node_modules/moment\0", 0x7FFF5FBFE5D8, 0x9)          = -1 Err#2
stat64("/Users/pierre/Projects/require_test/lib/sub/node_modules/moment.js\0", 0x7FFF5FBFC270, 0x9)               = -1 Err#2
stat64("/Users/pierre/Projects/require_test/lib/sub/node_modules/moment.json\0", 0x7FFF5FBFC270, 0x9)             = -1 Err#2
stat64("/Users/pierre/Projects/require_test/lib/sub/node_modules/moment.node\0", 0x7FFF5FBFC270, 0x9)             = -1 Err#2
open("/Users/pierre/Projects/require_test/lib/sub/node_modules/moment/package.json\0", 0x0, 0x1B6)                = -1 Err#2
stat64("/Users/pierre/Projects/require_test/lib/sub/node_modules/moment/index.js\0", 0x7FFF5FBFE578, 0x1B6)               = -1 Err#2
stat64("/Users/pierre/Projects/require_test/lib/sub/node_modules/moment/index.json\0", 0x7FFF5FBFE578, 0x1B6)             = -1 Err#2
stat64("/Users/pierre/Projects/require_test/lib/sub/node_modules/moment/index.node\0", 0x7FFF5FBFE578, 0x1B6)             = -1 Err#2

This PR divides by 7 the number of syscalls when requiring a module from a directory without node_modules at the cost of adding 1 from a directory with.

From my tests with a whole process doing only require('express'), I pass from 760 stat64 to 574 (-25%) and from 106 open_nocancel to 58 (45%).

Merge request reports