Re: [PATCH 0/4] crypto/arm64: reduce impact of NEON yield checks

2018-07-26 Thread bige...@linutronix.de
On 2018-07-26 09:25:40 [+0200], Ard Biesheuvel wrote: > Thanks a lot. > > So 20 us ~= 20,000 cycles on my 1 GHz Cortex-A53, and if I am > understanding you correctly, you wouldn't mind the quantum of work to > be in the order 16,000 cycles or even substantially more? I have currently that one

Re: [PATCH 1/4] crypto/arm64: ghash - reduce performance impact of NEON yield checks

2018-07-25 Thread bige...@linutronix.de
On 2018-07-25 06:57:42 [+], Vakul Garg wrote: > I tested this patch. It helped but didn't regain the performance to previous > level. > Are there more files remaining to be fixed? (In your original patch series > for adding > preemptability check, there were lot more files changed than this

Re: [PATCH 1/4] crypto/arm64: ghash - reduce performance impact of NEON yield checks

2018-07-25 Thread bige...@linutronix.de
On 2018-07-25 07:04:55 [+], Vakul Garg wrote: > > > > What about PREEMPT_NONE (server)? > > Why not have best of both the worlds :) the NEON code gets interrupted because another tasks wants to schedule and the scheduler allows. With "low latency desktop" this gets right done away. The

Re: [PATCH 0/4] crypto/arm64: reduce impact of NEON yield checks

2018-07-25 Thread bige...@linutronix.de
On 2018-07-25 11:54:53 [+0200], Ard Biesheuvel wrote: > Indeed. OTOH, if the -rt people (Sebastian?) turn up and say that a > 1000 cycle limit to the quantum of work performed with preemption > disabled is unreasonably low, we can increase the yield block counts > and approach the optimal numbers