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<div class="moz-cite-prefix"><font face="Calibri">Hi,<br>
<br>
After several hours of exhaustive tests I'm not certain it is
the same issue, managed to identify the problem, not the memory
increase but the reason for the slowdown.<br>
<br>
<b>Tests performed:</b><br>
1) To test for the issue you mentioned. Ran several versions of
Blender with GTX 580m set as Blender display device or purely as
GPGPU with an HD 3000 driving the display. Result: no noticeable
speed variance.<br>
<br>
2) Created heavy test .blend (link below) with displacement and
hair. Result: no noticeable speed variance but evidence of
increased memory usage with all recent versions of Blender. <br>
<br>
3) Removed all textures from my original heavy scene. Result:
solved big render slowdown but still evidence of increased
memory usage.<br>
<br>
<b>Blender versions test</b><b>ed:</b><br>
2.70a Hash f93bc76 (4th April)<br>
2.70.2 Hash 4ed16bc (17th April)<br>
2.70.4 Hash a8eb95c (27th April) - Memory increase appears in
and after this version, don't have versions between 17th and
27th to test.<br>
2.70.5 Hash 34bc1e5 VC12 (8th May)</font><br>
<font face="Calibri">2.70.5 Hash 7891899 VC12 (9th May)<br>
</font><font face="Calibri">2.70.5 Hash 30361a7 VC12 (13th May)<br>
2.70.5 Hash be980b9 VC12 (16th May)<br>
2.70.5 Hash 2e20c16 (16th May)<br>
<br>
<b>Conclusion</b><b> with my heavy scene:</b><br>
Windows 7 x64, GTX 580m 2GB.<br>
With Blender 2.70a total memory used 1540, since recent Blender
versions use more memory (1743) for the same scene there is
limited space left for render kernel. Removing just one of my
high resolution textures also works, then total memory used is
1688, it would seem the kernel needs at least 300MB spare for
full performance? Less than that and performance is severely
affected, two minute render becomes a ten minute render, could a
'Low memory - renders will possibly be slower' warning be
displayed in the render header? <br>
<br>
Can't find a reason for memory usage increase however so
supplied test .blend (below).<br>
<br>
<br>
Also noticed. Is it by design that F12 render preview now only
updates Power of 2 -1 for </font><font face="Calibri"><font
face="Calibri">each consecutive update</font>? This is okay
for low sample amounts but for renders with a few thousand
samples as the render progresses it appears nothing is happening
or Cycles has frozen and may prompt a user to cancel the render.<br>
<br>
Memory usage test scene .blend link to compare 2.70a and recent
versions.<br>
<a class="moz-txt-link-freetext" href="http://www.pasteall.org/blend/29276">http://www.pasteall.org/blend/29276</a><br>
<br>
Thank you,<br>
<br>
David<br>
</font>
<div class="moz-signature"><br>
<br>
<p style="font-size:x-small"><a
href="http://www.3d-designs-davidblack.blogspot.com">3d-designs-davidblack.blogspot.com</a></p>
</div>
On 18/05/2014 15:04, Brecht Van Lommel wrote:<br>
</div>
<blockquote
cite="mid:CAKFUgC3vp=EBiF-Ka6LQXtXvvCH9XGA7GDZekhFfiS0h9QXB6Q@mail.gmail.com"
type="cite">
<pre wrap="">Also, could you mention the commit hash numbers of the builds you
tested. There were a number of relevant changes on the 17th, so it's
not clear if they are included or not in that range.
Thanks,
Brecht.
On Sun, May 18, 2014 at 3:57 PM, Brecht Van Lommel
<a class="moz-txt-link-rfc2396E" href="mailto:brechtvanlommel@pandora.be"><brechtvanlommel@pandora.be></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi David,
Thanks for the tests. I think it's probably the same issue as this bug
report, so you can put your findings there:
<a class="moz-txt-link-freetext" href="https://developer.blender.org/T40027">https://developer.blender.org/T40027</a>
I'm not sure where the increased memory usage would come from, I can't
see any commit in that date range that would explain that.
Brecht.
On Sat, May 17, 2014 at 7:08 PM, David Black <a class="moz-txt-link-rfc2396E" href="mailto:db4tech@yahoo.co.uk"><db4tech@yahoo.co.uk></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi Brecht,
Spent the afternoon carrying out performance tests on a heavy scene (lots of
displacement and hair), sorry scene is test work for a company so unable to
share.
GPGPU tests performed with an 2GB GTX 580m
Small border region render of whole scene (F12 final render)
Blender 2.70a
Time:02:13 Mem:1540
Blender 2.70.4 (and .5)
Time:10:53 Mem:1743
In case there are several accumulating factors involved (other than
__launch_bounds__ ), after testing many Blender versions managed to narrow
down dates, big slowdown and increased memory usage was introduced between
17th and 27th April.
Also, post slowdown, render preview does not begin until the 12th sample,
thought the render and/or Blender had frozen? Synchronizing objects and BVH
build time is also slightly slower.
Would you like me to open a bug report?
Hope above information is in some way helpful.
David
3d-designs-davidblack.blogspot.com
On 25/04/2014 16:44, Brecht Van Lommel wrote:
Hi all,
We're having some trouble with CUDA performance at the moment, with in
a performance regression on Titan cards compared to 2.69, and unclear
effects from recent changes. Further there's the new CUDA 6.0 toolkit,
which we ideally could move to, as sticking to 5.0 is a problem with
newer compilers.
We could use some help testing all this, especially for Titan cards as
I don't have one of those.
There's a google doc here:
<a class="moz-txt-link-freetext" href="https://docs.google.com/spreadsheets/d/1IKvO6s7h_0oVGbGE3giowx2fBvyXzIfdM3qCSfROJfI">https://docs.google.com/spreadsheets/d/1IKvO6s7h_0oVGbGE3giowx2fBvyXzIfdM3qCSfROJfI</a>
For now I'm assuming someone with a Titan card can make own builds to
test these git revisions. If not we can build and upload binaries to
test.
The test is:
* download: <a class="moz-txt-link-freetext" href="http://www.pasteall.org/blend/28679">http://www.pasteall.org/blend/28679</a>
* run: ./blender -b modified_bmw.blend -f 1
If you've got a different .blend file that is giving performance
regressions, or you find different behavior when rendering in the UI
rather than command line, then results from that are welcome too.
The information that I'm looking for from this is especially:
* Which revision caused the Titan performance regressions?
* Is CUDA 6.0 performance acceptable to us for the next release?
* Were there significant performance regressions due to recent changes?
* Which effect do the two provided patches have when building with CUDA 6.0?
Thanks,
Brecht.
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</blockquote>
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