Is there an option to limit CPU core count / usages?

[kwonoj]

Trying to make migration poc for the large code base and due to some legacy codebase we are experiencing initial build takes some time. It is fine, but at some stage of build rspack seems excessively occupies CPU (or ram) usage makes other system activites feel hang - literally whole UI stops and hourglass icon appears around 20~30sec.

I'm curious if there's a way to set the limit for the CPU core count or similar, so it may take longer but won't block system use while dev waiting for it.

[hardfist]

try set TOKIO_WORKER_THREADS and RAYON_NUM_THREADS, in the future we may support RSPACK_WORKER_THREADS to control both

[kwonoj]

I gave it a try with TOKIO_WORKER_THREADS=4 RAYON_NUM_THREADS=4 rspack serve, but still observing same thing. Is there a way to diagnose this?

[kwonoj]

Ok, trying a bit more it looks like it's not a fault of rspack. If I use sass-loader with implementation sass-embedded, it seems spawning huge numbers of process at once (we have > 2000 scss modules) and it chokes up the CPU. Could workaround by not using sass-embedded, but would be good if rspack could throttle the number of the process spawned by loader or plugins.