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).
Background: that switch controls the way of memory transfer between host
and OpenCL device, namely the use of pre-pinned memory. When the flag
was introduced it did only make some improvements on AMD/ATI devices,
while at that time NVIDIA devices would show no or a slight negative
effects. Therefore the flag is set to FALSE by default. It seems that
newer NVIDIA drivers get extremely slow if the default non-pinned memory
transfer method is used.
If my findings are confirmed we will change the default setting of that
flag for new installations. Users of existing installations will need to
change the config flag manually.
Please check and report back.
Ulrich
Am 14.09.2016 um 00:47 schrieb I. Ivanov:
I find it strange...
When I upgraded from 14.04 to 16.04 - DT was at version 2.0.5 and nvidia
361. I actually experienced speed "gain" - did not clock it but it was
very noticeable. I worked in this state for several weeks - all happy,
no changes in settings to DT.
2.0.6 was installed on 2016-09-06. I noticed it works but did not test
any further. Then I didn't use the computer till 11th. Installed the
following updates
2016-09-11 19:56:16 status installed gnome-menus:amd64 3.13.3-6ubuntu3.1
2016-09-11 19:56:16 status installed desktop-file-utils:amd64 0.22-1ubuntu5
2016-09-11 19:56:17 status installed mime-support:all 3.59ubuntu1
2016-09-11 19:56:17 status installed bamfdaemon:amd64
0.5.3~bzr0+16.04.20160701-0ubuntu1
2016-09-11 19:56:17 status installed man-db:amd64 2.7.5-1
2016-09-11 19:56:18 status installed libc-bin:amd64 2.23-0ubuntu3
2016-09-11 19:56:18 status installed dbus:amd64 1.10.6-1ubuntu3
2016-09-11 19:56:18 status installed gconf2:amd64 3.2.6-3ubuntu6
2016-09-11 19:56:18 status installed hicolor-icon-theme:all 0.15-0ubuntu1
2016-09-11 19:56:18 status installed libglib2.0-0:i386
2.48.1-1~ubuntu16.04.1
2016-09-11 19:56:18 status installed libglib2.0-0:amd64
2.48.1-1~ubuntu16.04.1
2016-09-11 19:56:18 status installed sgml-base:all 1.26+nmu4ubuntu1
2016-09-11 19:56:19 status installed google-chrome-stable:amd64
53.0.2785.101-1
2016-09-11 19:56:19 status installed libp11-kit0:amd64
0.23.2-5~ubuntu16.04.1
2016-09-11 19:56:19 status installed libp11-kit0:i386 0.23.2-5~ubuntu16.04.1
2016-09-11 19:56:19 status installed p11-kit-modules:amd64
0.23.2-5~ubuntu16.04.1
2016-09-11 19:56:19 status installed libaccountsservice0:amd64
0.6.40-2ubuntu11.2
2016-09-11 19:56:19 status installed accountsservice:amd64
0.6.40-2ubuntu11.2
2016-09-11 19:56:19 status installed file-roller:amd64 3.16.5-0ubuntu1.2
2016-09-11 19:56:19 status installed gnome-font-viewer:amd64 3.16.2-1ubuntu1
2016-09-11 19:56:19 status installed libappstream-glib8:amd64
0.5.13-1ubuntu3
2016-09-11 19:56:19 status installed libimlib2:amd64 1.4.7-1ubuntu0.1
2016-09-11 19:56:19 status installed metacity-common:all 1:3.18.7-0ubuntu0.1
2016-09-11 19:56:19 status installed libmetacity-private3a:amd64
1:3.18.7-0ubuntu0.1
2016-09-11 19:56:19 status installed libnm-gtk-common:all
1.2.0-0ubuntu0.16.04.4
2016-09-11 19:56:19 status installed libnm-gtk0:amd64 1.2.0-0ubuntu0.16.04.4
2016-09-11 19:56:19 status installed libnma-common:all
1.2.0-0ubuntu0.16.04.4
2016-09-11 19:56:19 status installed libnma0:amd64 1.2.0-0ubuntu0.16.04.4
2016-09-11 19:56:19 status installed network-manager-gnome:amd64
1.2.0-0ubuntu0.16.04.4
2016-09-11 19:56:21 status installed snapd:amd64 2.14.2~16.04
2016-09-11 19:56:21 status installed p11-kit:amd64 0.23.2-5~ubuntu16.04.1
2016-09-11 19:56:21 status installed libc-bin:amd64 2.23-0ubuntu3
and noticed drop in performance - mainly when using darktable (not much
light table). Took a chance to turn off open CL and the performance
improved. After reading the thread
https://www.mail-archive.com/darktable-dev@lists.darktable.org/msg01176.html
Tried to compare with export of a single image.
without open CL - 23s for about 20 MB RAW.
Same image - no change
with open CL - 41s
The OS and the images are stored on SSD so the networking does not come
into play.
I can work without open CL - it is not a deal breaker but the behavior
is surprising.
Regards,
B
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