After upgrading to webpack 5 in our project we noticed that rebuild time increased more than 2 times comparing to webpack 4.

I've created a test repo https://github.com/meskill/webpack5-performance-issue to show the difference in rebuild time for webpack4 and webpack5.

It shows more than 2-time slowness of rebuild in webpack5 compare to webpack4. Profiling shows similar info

Cpuprofile for both webpack4 and webpack5