On 14/11/19(Thu) 17:30, Lauri Tirkkonen wrote: > [...] > The first test I made was on a beefy virtual machine under Hyper-V, > with 32 vCPUs on a Threadripper 2950X. With and without this patch (and > the followup for share/mk), I did make -j32 -C /usr/src/usr.bin. The > results were very disappointing: with my patches the build was *slower* > even though it used way more CPU. I think 'top' said it best: > > 32 CPUs: 0.1% user, 0.0% nice, 3.9% sys, 95.4% spin, 0.0% intr, 0.7% idle > ^^^^^^^^^^
I'd suggest considering the %user time when working on a userland tool. A high %spin time indicates that syscalls and page faults are spending a lot of time busy waiting on the KERNEL_LOCK(). In other words you're exposing the non-scalability of OpenBSD on such machine. I'd suggest you use less jobs, I'd try 8 or 12 as a first step. You can also write Makefiles that expose less the limitation of the system. ktrace(1) is your friend for that.
