Re: [PATCH] drm/radeon: Inline r100_mm_rreg

[Lauri Kasanen <cand@gmx.com>]

On Fri, 11 Apr 2014 10:33:08 +0200
Christian König <deathsimple@vodafone.de> wrote:

> >> Actually direct register access shouldn't be necessary so often. Apart
> >> from page flips, write/read pointer updates and irq processing there
> >> shouldn't be so many of them. Could you clarify a bit more what issue
> >> you are seeing here?
> > Too much cpu usage for such a simple function. 2% makes it #2 in top-10
> > radeon.ko functions, right after evergreen_cs_parse. For reference, #3
> > (radeon_cs_packet_parse) is only 0.5%, one fourth of this function's
> > usage.
> 
> I think you misunderstood me here. I do believe your numbers that it 
> makes a noticeable difference.
> 
> But I've did a couple of perf tests recently on SI and CIK while hacking 
> on VM support, and IIRC r100_mm_rreg didn't showed up in the top 10 on 
> those systems.
> 
> So what puzzles me is who the hack is calling r100_mm_rreg so often that 
> it makes a noticeable difference on evergreen/NI?

The biggest caller is cayman_cp_int_cntl_setup. Before inlining it took
0.0013%, after it takes 1%.

This is on a Richland APU, so Aruba/Cayman. Urban Terror is an ioq3
game with a lot of cpu-side vertex submissions.

- Lauri