This is mainly in reference to project 1867, these workunits in specific:
http://burp.renderfarming.net/workunit.php?wuid=1983677
http://burp.renderfarming.net/workunit.php?wuid=1983837

I have a long record of workunits for project 1867, all of which have validated properly against others using Blender v4.79

These units in specific have been rendered using Blender v4.78 (Why??) and have failed to verify against my newer Blender v4.79 render, resulting in me getting 0 credit for the workload.

Surely the newer version of Blender is more likely to have the correct render result? Should it not be sent out for verification to someone with Blender v4.79?

Linux clients are v4.78 whereas the Windows are 4.79 at present. The difference in version number is related to a small change in the Windows version not affecting renders. Both carry the same version of Blender with them.
What we're seeing here is probably that Windows and Linux versions of the same version of Blender disagree on how to render something.

What we're seeing here is probably that Windows and Linux versions of the same version of Blender disagree on how to render something.

Oh, that's a much more serious issue than I first anticipated :(

Is this something that can be reported and fixed upstream?

Typically the difference is very small and has to do with rounding errors being treated slightly different on different platforms. When that is the case you typically get credit for the unit later. For large issues (like back when normal maps where completely flipped on Windows as compared to Linux) we isolate the issue and report it upstream. If those kind of issues are not fixed it will cause flickering as some frames are rendered on Linux and some on Windows etc.

Haven't we had this problem before? IIRC, that's why some sessions were rendered entirely in either Windows or Linux, but not both.

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Click here to see My Detailed BOINC Stats

Typically the difference is very small and has to do with rounding errors being treated slightly different on different platforms. When that is the case you typically get credit for the unit later. For large issues (like back when normal maps where completely flipped on Windows as compared to Linux) we isolate the issue and report it upstream. If those kind of issues are not fixed it will cause flickering as some frames are rendered on Linux and some on Windows etc.

The project is now finished, and looking at the MP4, it looks... odd. I'm not sure if that's the way it's meant to look, but there are definitely frames jumping around the place.

It seems there is a serious issue with either the Linux Blender version in general or the software they've been provided. I commonly see Blender versions v4.78 (Linux) erroring on many project workunits. Not sure if these two things are related or not.

Typical output on Linux (Ubuntu 13.10), and I'm not the only one:

./blender: error while loading shared libraries: __vdso_time: invalid mode for dlopen(): Invalid argument
|[-->] Info:
|child <3312> to stdout
|0 - ./blender_ld
|1 - --library-path
|2 - ./lib
|3 - ./blender

---------------------------
Exception caught: Worker application apparently died prematurely
Status: -9
---------------------------
Calling boinc_finish()...
02:17:40 (3308): called boinc_finish

I would be highly sceptical of the results of Linux users that aren't erroring.

Is this not an easy fix? Eventually I want to move all my computing to Linux, but I need to check things off a list before I can do that. Broken BURP on Linux is one of those things. :(

Most development here is made in batches where focus is on one thing for a while then switches to another. Currently focus is on server stuff with Payday, website/backend upgrades and installation of fibre optical cable on the near horizon. After that focus changes to the client once again with Glue3 and Blender code changes being merged in from the Sunflower clients, then back to server stuff and so on.

A complete list of issues can be found here: http://development.burp.renderfarming.net/projects/burp/issues

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I didn't realize that tracker existed, thanks. I hope that happens this year as I'd like to move over this year.