svn commit: r343125 - head/sys/dev/ioat

[Conrad Meyer]

On Thu, Jan 17, 2019 at 4:12 PM Kevin Bowling <kevin.bowling at kev009.com> wrote:
>
> Out of curiosity are you using this driver? Any performance data?

Yep.

I don't have any hard numbers on hand but my recollection is it caps
out at about 5 GB/s, total, on Broadwell.  Our workload with it is
predominantly unmapped 8kB copies but includes some 512 byte copies as
well.  My recollection is that the channels are logical and share a
single DMA engine, so there's not much reason to use more than one of
them.  It may improve on future microarchs but I can't speak to those.

Cheers,
Conrad