No appreciable difference

darktable 2.0.6 running in ubuntu 16.04 LTS 64 bit vm in slackware 14.2
64 bit host.


On 09/15/2016 01:14 AM, Ulrich Pegelow wrote:
> Well, in your case I see the differences as only marginal - the time
> spent in the OpenCL pixelpipe differs only by 2% between the two
> setting (in favor of TRUE). Not sure if differences persist if you
> would repeat profiling several times to get out any fluctuations.
>
> So it seems that your combination of GPU and driver does not profit
> from the opencl_use_pinned_memory flag. But in your case it would not
> harm either to change the default to TRUE.
>
> To others: I am interested to see if there are systems where
> opencl_use_pinned_memory=TRUE gives a heavy negative impact on
> performance.
>
> Ulrich
>
> Am 15.09.2016 um 06:00 schrieb Jack Bowling:
>> On 09/14/2016 09:56 AM, Ulrich Pegelow wrote:
>>> Well, there obviously is an issue with OpenCL and NVIDIA. However, a
>>> quick check reveals that this is not related to 2.0.6 versus 2.0.5.
>>>
>>> In fact it seems that NVIDIA did some changes to their drivers in the
>>> way they handle memory transfers over the IDE interface.
>>>
>>> There is a quick fix for that in darktable. You can switch config
>>> variable opencl_use_pinned_memory to TRUE (can be found in
>>> darktablerc).
>>> At least here on my this makes a difference of up to a factor of 30
>>> (oldish GeForce GTS 450 and 367.35 driver).
>> <snip>
>>
>> Setting pinned_memory=true leads to slower render times on my box. Here
>> is system info on my fully updated Ubuntu 16.04 box:
>>
>> $ darktable --version
>> this is darktable 2.0.6
>> copyright (c) 2009-2016 johannes hanika
>> darktable-dev@lists.darktable.org
>>
>> compile options:
>>   bit depth is 64 bit
>>   normal build
>>   OpenMP support enabled
>>   OpenCL support enabled
>>   Lua support enabled, API version 3.0.0
>>   Colord support enabled
>>   gPhoto2 support enabled
>>   GraphicsMagick support enabled
>>
>> $ inxi
>> CPU~Octa core AMD FX-8300 Eight-Core (-MCP-) speed/max~1400/3300 MHz
>> Kernel~4.4.0-36-generic x86_64 Up~8 days Mem~2495.3/32090.4MB
>> HDD~23734.6GB(33.4% used) Procs~340 Client~Shell inxi~2.2.35
>>
>> $ inxi -G
>> Graphics:  Card: NVIDIA GK107 [GeForce GT 740]
>>            Display Server: X.Org 1.18.3 drivers: nvidia (unloaded:
>> fbdev,vesa,nouveau)
>>            Resolution: 2560x1440@59.95hz
>>            GLX Renderer: GeForce GT 740/PCIe/SSE2
>>            GLX Version: 4.5.0 NVIDIA 361.42
>>
>> Here is the relevant paste from my darktable config:
>>
>> opencl=TRUE
>> opencl_async_pixelpipe=false
>> opencl_avoid_atomics=false
>> opencl_checksum=4188966525
>> opencl_device_priority=*/!0,*/*/*
>> opencl_library=
>> opencl_memory_headroom=1000
>> opencl_memory_requirement=768
>> opencl_micro_nap=1000
>> opencl_number_event_handles=25
>> opencl_omit_whitebalance=
>> opencl_size_roundup=16
>> opencl_synch_cache=false
>> opencl_use_cpu_devices=false
>> opencl_use_pinned_memory=false
>>
>> Note the high headroom necessary to prevent atrous dumping to CPU.
>>
>> Attached are two text files of "darktable -d opencl -d perf" output, one
>> with pinned_memory=true and one with pinned_memory=false.
>>
>> Jack
>>
>
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-- 
Pete Hall
p...@hallcircus.net
608-290-0731


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