[Mesa-dev] [RFC 3/3] anv: Do relocations in userspace before execbuf ioctl

[Chris Wilson]

On Tue, Nov 01, 2016 at 08:07:36AM +0000, Chris Wilson wrote:
> On Mon, Oct 31, 2016 at 09:48:15PM -0700, Jason Ekstrand wrote:
> > + * By doing relocations on the CPU, we can tell the kernel that it doesn't
> > + * need to bother.  We want to do this because the surface state buffer is
> > + * used by every command buffer so, if the kernel does the relocations, it
> > + * will always be busy and the kernel will always stall.
> 
> Userspace relocation + NO_RELOC processing should also work out to be
> fastest of the available approaches today. If you want to try an ignore
> stalls flag, it shouldn't take too long to write (I'll get that done
> today) and then you can compare the overhead of the kernel having to copy
> the relocations from userspace. (You also want the fast execbuf relocation
> processing patches from a few years ago...)

https://cgit.freedesktop.org/~ickle/linux-2.6/commit/?h=prescheduler&id=767804fe12608d905ba0b4e9590706537caa9956
[compile tested]
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre