[Soc-2013-dev] Weekly Report #5 Threaded Dependency Graph

[Sergey Sharybin]

Hi,

Leaving to SIGGRAPH quite early tomorrow morning, so here's current report.

= This week =

Quite some time was spent on finishing release logs, looking into some
last-minute reports and so on.

As for the project, i was working on solving some weird slowdown on
multi-core CPU, which ends up in like 1.5-2x times slower than it will
ideally could be.

Root of the issue goes to the guarded allocator adding some overhead
(MemHead+MemTail) around each block, which leads to much less cache
efficiency when handling DeformVerts and DeformWeights.

Ideally we'll need to get rid of bunch of small allocations. Currently
looking into a patch which originally came from Joedh and Campbell, which
switches DeformWeights allocations to memory pool. Original patch doesn't
give any speedup, but after some tweaks it seems it might be close enough
to performance of bare mallocs.

Didn't fully finish the patch yet, would work over the weekend perhaps.

Another things i did are:

- Added some timing measurements to the threaded update, which helps to see
what each thread was doing and for how long.
- VBOs seems to be working fine now, and no workarounds are needed now.

= Next week =
* Would need to figure out how to deal with dupligroups (currently there's
some nsty code, which doesn't seem to be needed), Joshua's feedback would
be needed here. We'll talk in IRC.
* Will look into local graphs for renderer and viewport.
* And yes, this is all from previous week :(
* Finish DeformWeights patch

<strong>Questions</strong>.
We're solving issues with Campbell and Brecht in irc and over personal
mails, but nothing to be raised here.


-- 
With best regards, Sergey Sharybin
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