Weird CPU caching behaviour (Ryzen 1950x)

Not really sure where else to ask this, hoping I’m not the only one.

One thing I’ve noticed is sometimes, for whatever reason, my 1950x (threadripper) will start to feel sluggish. The clocks remain stable and I don’t see any obvious errors (AER for example)…

Purely by coincidence one way I’ve been able to fix it is disabling the CPU cache and reenabling it on all cpus. The difference is quite perceivable.

I’m aware there are … unique, scheduling challenges especially with early Ryzen, I don’t believe this is any of them because process to CPU locality doesn’t affect it. Pure speculation but it’s almost like either the cache is getting turn off by something else or the act of toggling it causes some other state reset? (Power management for example).

Has anyone run into anything like this? 4.19 kernel. All cores locked at 4.0GHz.

One other weird behaviour is the system clock becomes much, much more stable (both TSC and HPET).

Your issue is exactly the cpu scheduler. Kernel 4.19 may be supporting a 1950X, but I would consider using a newer kenel or rolling os.

Do you have a link? The issue with sluggishness resolves itself after toggling the CPU cache.