On 2/13/22, Jason A. Donenfeld <Jason@xxxxxxxxx> wrote: > Hey Sebastian, > > On Fri, Feb 11, 2022 at 6:26 PM Sebastian Andrzej Siewior > <bigeasy@xxxxxxxxxxxxx> wrote: >> Sure. I can do the CPU-HP notifier later one once we are done with >> everything. I acked the v7, don't see a road block. > > I've been running this over the weekend and performance is generally okay. > > # perf top --symbols $(objdump -t > /usr/src/linux/drivers/char/random.o|fgrep 'F .text'|awk '{print > $6}'|tr '\n' ,) -F max -g > > One thing I noticed though was that add_interrupt_randomness spends > most of its time on: > > lock xadd %eax,0x38(%rbp) > > So, as expected, those atomics really need to go. Indeed we might be > best off with the CPU hotplug notifier for setting the count back to > zero. > > Do you want to prepare a patch for this? Or should I take a stab at it? FYI, I was overwhelmed with a compulsion to try doing it myself and posted that here https://lore.kernel.org/lkml/20220213215343.11652-1-Jason@xxxxxxxxx/ which is now pending your review.