Hi Thomas, I'm trying to optimize this for crypto performance while still taking into account preemption concerns. I'm having a bit of trouble figuring out a way to determine numerically what the upper bounds for this stuff looks like. I'm sure I could pick a pretty sane number that's arguably okay -- and way under the limit -- but I still am interested in determining what that limit actually is. I was hoping there'd be a debugging option called, "warn if preemption is disabled for too long", or something, but I couldn't find anything like that. I'm also not quite sure what the latency limits are, to just compute this with a formula. Essentially what I'm trying to determine is: preempt_disable(); asm volatile(".fill N, 1, 0x90;"); preempt_enable(); What is the maximum value of N for which the above is okay? What technique would you generally use in measuring this? Thanks, Jason