Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction | Date | Wed, 11 Nov 2015 09:49:48 +0100 |
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On Tuesday 10 November 2015 18:52:45 Z Lim wrote: > On Tue, Nov 10, 2015 at 4:42 PM, Alexei Starovoitov > <alexei.starovoitov@gmail.com> wrote: > > On Tue, Nov 10, 2015 at 04:26:02PM -0800, Shi, Yang wrote: > >> On 11/10/2015 4:08 PM, Eric Dumazet wrote: > >> >On Tue, 2015-11-10 at 14:41 -0800, Yang Shi wrote: > >> >>aarch64 doesn't have native support for XADD instruction, implement it by > >> >>the below instruction sequence: > > aarch64 supports atomic add in ARMv8.1. > For ARMv8(.0), please consider using LDXR/STXR sequence.
Is it worth optimizing for the 8.1 case? It would add a bit of complexity to make the code depend on the CPU feature, but it's certainly doable.
Arnd
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