lkml.org 
[lkml]   [2009]   [Jun]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: TTM page pool allocator
Dave Airlie skrev:
> On Thu, Jun 25, 2009 at 10:01 PM, Jerome Glisse<glisse@freedesktop.org> wrote:
>
>> Hi,
>>
>> Thomas i attach a reworked page pool allocator based on Dave works,
>> this one should be ok with ttm cache status tracking. It definitely
>> helps on AGP system, now the bottleneck is in mesa vertex's dma
>> allocation.
>>
>>
>
> My original version kept a list of wb pages as well, this proved to be
> quite a useful
> optimisation on my test systems when I implemented it, without it I
> was spending ~20%
> of my CPU in getting free pages, granted I always used WB pages on
> PCIE/IGP systems.
>
> Another optimisation I made at the time was around the populate call,
> (not sure if this
> is what still happens):
>
> Allocate a 64K local BO for DMA object.
> Write into the first 5 pages from userspace - get WB pages.
> Bind to GART, swap those 5 pages to WC + flush.
> Then populate the rest with WC pages from the list.
> Granted I think allocating WC in the first place from the pool might
> work just as well since most of the DMA buffers are write only.
>

Yes, I think in the latter case the user-space driver should take care
to specify WC from the beginning, when the BO is allocated.

BTW is there any DMA buffer verification taking place on WC buffers on
Radeon?

> Dave.
>

/Thomas



\
 
 \ /
  Last update: 2009-06-26 08:35    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site