The Scottish Boinc Team

Posted: **Thu Oct 31, 2019 11:45 am**

help - my cosmology WU error out on some Linux machines ... <message>
process exited with code 193 (0xc1, -63)</message>
<stderr_txt>
2019-10-31 11:28:44 (16426): vboxwrapper (7.7.26197): starting
SIGSEGV: segmentation violation
Stack trace (8 frames):
../../projects/www.cosmologyathome.org/vboxwrapper_261 ... )[0x47ec3d]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x13f40)[0x7fe126f08f40]
/lib/x86_64-linux-gnu/libc.so.6(+0xb01d6)[0x7fe126dba1d6]
../../projects/www.cosmologyathome.org/vboxwrapper_261 ... u[0x45441c]
../../projects/www.cosmologyathome.org/vboxwrapper_261 ... u[0x40da75]
../../projects/www.cosmologyathome.org/vboxwrapper_261 ... u[0x406d3b]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xeb)[0x7fe126d30b6b]
../../projects/www.cosmologyathome.org/vboxwrapper_261 ... u[0x405479]

Exiting...

Posted: **Thu Oct 31, 2019 1:25 pm**

On some machines if you don't have enough threads running it then they will error out. That limit seems to change over time. I've had machines that would work fine with 4 threads but a month later they need 6 or 8 to be successful. I ran some in Sept and this is the app_config I ran on the 2990WXs.

Code: Select all

<app_config>
<app>
<name>camb_boinc2docker</name>
<max_concurrent>5</max_concurrent>
</app>
<app_version>
<app_name>camb_boinc2docker</app_name>
<plan_class>vbox64_mt</plan_class>
<avg_ncpus>6</avg_ncpus>
<max_ncpus>6</max_ncpus>
</app_version>

<project_max_concurrent>64</project_max_concurrent>
</app_config>

Looking at that I'm guessing I was running with HT off, which doesn't matter. I will also add that VBox really sucks on the 2990s due to their architecture. IIRC I could actually make more credits/day running the "Legacy" app which pays poorly. VietOz and I both confirmed this behavior on Cosmo and the 2990WX. Other AMD's or Intels do much better than the 2990.

Posted: **Thu Oct 31, 2019 1:37 pm**

I looked at a dual Intel box and I was running 7 threads/WU.

BTW, you do have to have VBox installed to run any apps except the Legacy WU. Legacy is single threaded but it doesn't pay as well as the docker app.

EDIT: Cosmo really doesn't use the threads efficiently so you don't want to use any more per WU that you have to ... a fine line there

Posted: **Thu Oct 31, 2019 1:40 pm**

Thanks. Vbox is installed on them all.

TBH, I am already losing the will to live with Cosmology, I was ready to hammer this sprint with everything I've got because we are just outside the points in the Marathon too. Could reasonably expect to pick up 30 or more FB points in one weekend

Posted: **Thu Oct 31, 2019 2:00 pm**

Due to the VBox requirement, Cosmo is one of my least favorite projects. The reason that I had turned HT OFF is that after I found my dual Intels were kicking the 2990s butt VietOz and I started experimenting. No matter how we set them up the 2990s perform quite a bit worse. I finally found a thread on the VBox forums saying the problem was the internal architecture of the 2990 ... 2 dies don't have direct memory access and the CPU's internal task scheduler screws up VBox.

Posted: **Thu Oct 31, 2019 2:11 pm**

might help to limit the 2990 machines to 32 threads?

Either that or just run WCG

Posted: **Thu Oct 31, 2019 2:21 pm**

There is NO setting on the 2990 that will make a difference ... been there and done that. Theoretically, if you only run 32 threads with HT ON then the internal scheduler of the CPU will put all working threads on the 1st 2 dies that have direct memory access. The 2nd 2 dies will be inactive. You won't be simulating HT Off you will just be using only 1/2 the CPU.

Posted: **Fri Nov 01, 2019 11:06 pm**

TSBT is winning, just, having spent all day catching up with Litomysl, who a little late in the year are finally taking FB seriously, staking their claim on a promotion place without coming close to challenging our supremacy.

Posted: **Sat Nov 02, 2019 12:49 am**

Keep up the good work guys. Sorry I'm out of this one. Busy returning some favors.

Posted: **Sun Nov 03, 2019 1:05 am**

No probs scole, we've got it! Not that we need to! We've already won league 2 by an obscene margin.
We'll have a bit more sport in League 1 next year. If FB survives, which I very much hope it does!

The Scottish Boinc Team

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