Messages in this thread | | | Date | Mon, 19 Dec 2011 20:51:15 +0100 | From | Thomas Hellstrom <> | Subject | Re: [PATCH] fixes to drm-next - TTM DMA code (v1) |
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On 12/13/2011 05:40 PM, Konrad Rzeszutek Wilk wrote: > On Tue, Dec 13, 2011 at 05:23:30PM +0100, Thomas Hellstrom wrote: > >> On 12/13/2011 05:07 PM, Jerome Glisse wrote: >> >>> On Mon, Dec 12, 2011 at 03:09:26PM -0500, Konrad Rzeszutek Wilk wrote: >>> >>>> Jerome pointed me to some accounting error in the DMA API debugging code and >>>> while I can't figure it out yet, I did notice some extreme slowness - which >>>> is due to the nouveau driver calling the unpopulate (now that unbind + >>>> unpopulate are squashed) quite a lot (this is using Gnome Shell - I think GNOME2 >>>> did not have those issues but I can't recall). >>>> >>>> Anyhow these patches fix the 50% perf regression I saw and also some minor bugs >>>> that I noticed. >>>> >>>> >>> Gonna review those today and test them. >>> >>> Cheers, >>> Jerome >>> >> Hi! >> >> I'm not whether any drivers are still using the AGP backend? >> > Uh, probably they do if the cards are AGP? > The problem I encountered was with an PCIe Nvidia card: > > 01:00.0 VGA compatible controller: nVidia Corporation G84 [GeForce 8600 GT] (rev a1 > > >> Calling unpopulate / (previous clear) each time unbind is done >> should be quite >> inefficient with that one, as AGP sets up its own data structures >> and copies page tables >> on each populate. That should really be avoided unless there is a >> good reason to have it. >> > nouveau_bo_rd32 and nv50_crtc_cursor_set showed up as the callers that > were causing the unpopulate calls. It did happen _a lot_ when I moved the > cursor madly. >
Konrad, Jerome Was there a resolution to this. If the ttm_tt rewrite results in unpopulate being called more often than before, and that causes performance regressions, that must be fixed as soon as possible.
/Thomas
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