Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 22 Mar 2018 10:07:23 -0700 | Subject | Re: [RFC PATCH 0/3] kernel: add support for 256-bit IO access |
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On Thu, Mar 22, 2018 at 5:48 AM, David Laight <David.Laight@aculab.com> wrote: > > So if we needed to do PIO reads using the AVX2 (or better AVX-512) > registers would make a significant difference. > Fortunately we can 'dma' most of the data we need to transfer.
I think this is the really fundamental issue.
A device that expects PIO to do some kind of high-performance transaction is a *broken* device.
It really is that simple. We don't bend over for misdesigned hardware crap unless it is really common.
> I've traced writes before, they are a lot faster and are limited > by things in the fpga fabric (they appear back to back).
The write combine buffer really should be much more effective than any AVX or similar can ever be.
Linus
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