Re: [RFC PATCH 0/5] running kernel mode SIMD with softirqs disabled

2021-02-16 Thread Ard Biesheuvel
On Tue, 16 Feb 2021 at 11:10, Peter Zijlstra wrote: > > On Fri, Dec 18, 2020 at 06:01:01PM +0100, Ard Biesheuvel wrote: > > [ TL;DR for the non-ARM folks on CC: disabling softirq processing when using > > SIMD in kernel mode could reduce complexity and improve performance, but > > we > > need

Re: [RFC PATCH 0/5] running kernel mode SIMD with softirqs disabled

2021-02-16 Thread Peter Zijlstra
On Fri, Dec 18, 2020 at 06:01:01PM +0100, Ard Biesheuvel wrote: > [ TL;DR for the non-ARM folks on CC: disabling softirq processing when using > SIMD in kernel mode could reduce complexity and improve performance, but we > need to decide whether we can do this, and how much softirq processing >

Re: [RFC PATCH 0/5] running kernel mode SIMD with softirqs disabled

2021-01-14 Thread Ard Biesheuvel
On Sat, 19 Dec 2020 at 03:05, Herbert Xu wrote: > > On Fri, Dec 18, 2020 at 06:01:01PM +0100, Ard Biesheuvel wrote: > > > > Questions: > > - what did I miss or break horribly? > > - does any of this matter for RT? AIUI, RT runs softirqs from a dedicated > > kthread, so I don't think it cares. >

Re: [RFC PATCH 0/5] running kernel mode SIMD with softirqs disabled

2020-12-18 Thread Herbert Xu
On Fri, Dec 18, 2020 at 06:01:01PM +0100, Ard Biesheuvel wrote: > > Questions: > - what did I miss or break horribly? > - does any of this matter for RT? AIUI, RT runs softirqs from a dedicated > kthread, so I don't think it cares. > - what would be a reasonable upper bound to keep softirqs disab

[RFC PATCH 0/5] running kernel mode SIMD with softirqs disabled

2020-12-18 Thread Ard Biesheuvel
[ TL;DR for the non-ARM folks on CC: disabling softirq processing when using SIMD in kernel mode could reduce complexity and improve performance, but we need to decide whether we can do this, and how much softirq processing latency we can tolerate. If we can find a satisfactory solution for t