On Wed, May 24, 2017 at 9:56 AM, Michel Dänzer <michel at daenzer.net> wrote: > On 23/05/17 07:38 PM, Marek Olšák wrote: >> On Tue, May 23, 2017 at 2:45 AM, Michel Dänzer <michel at daenzer.net> wrote: >>> On 22/05/17 07:09 PM, Marek Olšák wrote: >>>> On Mon, May 22, 2017 at 12:00 PM, Michel Dänzer <michel at daenzer.net> wrote: >>>>> On 20/05/17 06:26 PM, Marek Olšák wrote: >>>>>> On May 20, 2017 3:26 AM, "Michel Dänzer" <michel at daenzer.net >>>>>> <mailto:michel at daenzer.net>> wrote: >>>>>> >>>>>> On 20/05/17 01:14 AM, Marek Olšák wrote: >>>>>> > Hi Michel, >>>>>> > >>>>>> > I've applied your series >>>>>> >>>>>> Thanks for testing it. >>>>>> >>>>>> > and it doesn't help with low Dirt Rally performance on Fiji. I see TTM >>>>>> > buffer moves at 800MB/s and many VRAM page faults. >>>>>> >>>>>> Did you see this: >>>>>> >>>>>> >> Note that there's only little if any improvement of the average >>>>>> framerate >>>>>> >> reported, but the minimum framerate as seen on the HUD goes from >>>>>> ~10 fps >>>>>> >> to ~17. >>>>>> >>>>>> I.e. it mostly affects the minimum framerate and smoothness for me >>>>>> as well. >>>>>> >>>>>> >>>>>> Without the series, I get 70 average fps. With the series, I get 30 >>>>>> average fps. That might just be random bad luck. I don't know. >>>>> >>>>> Hmm, yeah, maybe that was just one of the random slowdowns you've been >>>>> talking about in other threads and on IRC? >>>>> >>>>> I can't reproduce any slowdown with these patches, even leaving visible >>>>> VRAM size at 256 MB. >>>> >>>> The random slowdowns with Dirt Rally are only caused by the pressure >>>> on visible VRAM. This whole thread is about those random slowdowns. >>> >>> No, this thread is about the scenario described in the cover letter of >>> this patch series. >>> >>> >>>> If you're saying "maybe it was just one of the random slowdowns", you're >>>> saying "maybe it was just the visible VRAM pressure". It's only >>>> random with Dirt Rally, which makes it difficult to believe statements >>>> such as "I can't reproduce any slowdown". >>> >>> I could say the same thing about you seeing random slowdowns... I've >>> never seen that, I had to artificially limit the size of visible VRAM to >>> 64 MB to make it significantly affect the benchmark result. >>> >>> How many times do you need to run the benchmark on average to hit a >>> random slowdown? Which desktop environment and other X clients are >>> running during the benchmark? Which tab is active in the Steam window >>> while the benchmark runs? >>> >>> In my case, it's only xfwm4, xterm and steam on the Dirt Rally page in >>> the library. >> >> Ubuntu Unity, Steam small mode (there are no tabs), Ultra settings in >> Dirt Rally. >> >> Every single time I run the game with this series, I get 700-1000MB/s >> of TTM BO moves. There doesn't seem to be any randomness. >> >> It was better without this series. (meaning it was sometimes OK, sometimes bad) > > Thanks for the additional details. I presume that in the bad case there > are some BOs lying around in visible VRAM (e.g. from Unity), which > causes some of Dirt Rally's BOs to go back and forth between GTT on CPU > page faults and VRAM on GPU usage. > > This means at least patch 2 goes out the window. I'll see if I can > salvage something out of patch 3. I think the final solution (done in fault_reserve_notify) should be: if (bo->num_cpu_page_faults++ > 20) bo->preferred_domain = GTT_WC; Otherwise I think we'll be just going in circles and not get anywhere. Marek
