[Intel-gfx] sna: Experimental support for write-combining mmaps (wc-mmap)

[Sedat Dilek]

On Fri, Nov 7, 2014 at 1:10 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Fri, Nov 07, 2014 at 01:00:32PM +0100, Sedat Dilek wrote:
>> Here some numbers...
>>
>> $ diff -uprN benchmarks/x11perf-aa10text_no-wcmmap.txt
>> benchmarks/x11perf-aa10text_wcmmap.txt
>> --- benchmarks/x11perf-aa10text_no-wcmmap.txt   2014-11-07
>> 12:57:49.932264840 +0100
>> +++ benchmarks/x11perf-aa10text_wcmmap.txt      2014-11-07
>> 12:53:17.028273399 +0100
>> @@ -2,16 +2,16 @@ $ x11perf -aa10text
>>  x11perf - X11 performance program, version 1.2
>>  The X.Org Foundation server version 11501000 on :0
>>  from fambox
>> -Fri Nov  7 12:56:29 2014
>> +Fri Nov  7 12:51:37 2014
>>
>> -Sync time adjustment is 0.0814 msecs.
>> +Sync time adjustment is 0.0817 msecs.
>>
>> -24000000 reps @   0.0002 msec (4420000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> -24000000 reps @   0.0002 msec (4420000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> -24000000 reps @   0.0002 msec (4380000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> -24000000 reps @   0.0002 msec (4410000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> -24000000 reps @   0.0002 msec (4410000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> -120000000 trep @   0.0002 msec (4410000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> +24000000 reps @   0.0002 msec (4490000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> +24000000 reps @   0.0002 msec (4490000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> +24000000 reps @   0.0002 msec (4480000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> +24000000 reps @   0.0002 msec (4490000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> +24000000 reps @   0.0002 msec (4490000.0/sec): Char in 80-char aa
>> line (Charter 10)
>> +120000000 trep @   0.0002 msec (4490000.0/sec): Char in 80-char aa
>> line (Charter 10)
>
> Hmm, what hw is that? As 4M is a bit on the low side.

[  1378.132] (II) intel(0): SNA initialized with Sandybridge (gen6, gt2) backend

Building intel-ddx with --enable-debug=full I see now...

$ egrep -i 'wc' /var/log/Xorg.0.log
[  1378.126] kgem_init: has wc-mmapping? 1
[  1379.122] __kgem_bo_map__gtt_or_wc: handle=6
[  1379.159] __kgem_bo_map__gtt_or_wc: handle=6
[  1379.303] __kgem_bo_map__gtt_or_wc: handle=6

- Sedat -