Forum > GPU crunching
Modified SETI MB CUDA + opt AP package for full GPU utilization
koschi:
--- Quote from: sunu on 24 Jan 2009, 09:36:58 am ---Just a FYI. Whatever I tried, flops, avg_ncpus, maxncpus in app_info.xml in order to force 3+1 in a quad didn't have any effect. The only thing that seems to work is
<avg_ncpus>1.3400</avg_ncpus>
<max_ncpus>1.3400</max_ncpus>
in AP section of app_info.xml. But that possibly means that If there is no MB work, only 3 cores will be used. Whatever I did in MB section seemed irrelevant.
--- End quote ---
Are you running SETI only?
I'm running some more projects and would like to run a 3+1 configuration, but whatever I set avg_ncpus/max_ncpus to (tried 0.04, 1, 1.5, 2), its doesn't work. When set to 2, no CUDA process is started at all. With all values >= 1 the given nice value is 19, not 10...
Is there detailed documentation of the app_info stuff somewhere that explains all tags?
I guess I have to use a cc_config.xml with ncpus 3 if there is no solution via app_info, right?
sunu:
I'm running astropulse+multibeam. Because of linux client's full core use we have to use 3+1. So I put those values in the AP section of app_info.xml. That did the trick. Whatever was in the MB section didn't seem to matter. Playing with cc_config.xml didn't have the desired effect. Please see above another post from me (reply #242) about cc_config.xml.
koschi:
This machine where I'm trying to set up MB CUDA and AP is running POEM, LHC and GPUGRID as well.
With ncpus=3 in cc_config I get the desired result (as long as I have MB WUs), but thats far away from being perfect, if there is no GPUGRID task (which happens from time to time) and it doesn't get work from SETI, one core is idle...
I've read your post regarding the AP settings (found it via google, hehe), but I'm a little confused, I doubt that it works when more projects are attached... Right now I don't get any AP WUs, only had some MB units earlier today, so I cant say if it runs MB and AP in parallel or not yet...
edit:
My goal is to run CPU units (POEM, SETI AP, LHC) and GPU units (SETI & GPUGRID) at the same time with the best utilization (better more then less, the scheduler can stand it...)
sunu:
As it is right now I think the problem lies with boinc client which cannot handle very well cpu- and gpu-bound tasks simultaneously.
Your situation is more complicated with all those projects that you want to run. I don't know whether the other projects use an app_info.xml file too, but if they do, you can put these two rows
<avg_ncpus>1.3400</avg_ncpus>
<max_ncpus>1.3400</max_ncpus>
on their respective CPU apps sections.
That way you will always run 3+1 except when there is no GPU task where you'll have 1 core idle. Then you can put ncpus 5 to cc_config.xml for some time until you get some GPU tasks to crunch again.
Regarding more is better than 1 core empty I think it is wrong. These optimized apps have special optimization for cache usage and when you have two apps, especially from different projects, sharing a core you will have degraded performance overall with all these cache misses or whatever. On the other hand you will always have some seti cuda or GPUGRID tasks to crunch more or less. On those rare circumstances that you will not, you can use the cc_config.xml trick.
koschi:
I changed the AP ncpus from 0.0400 to 1.34 in SETIs app_info.xml...
But as long as there is no AP WU running this is not effective I think. My app_info should be OK, but I didn't get a single new WU since this afternoon. Had some MBs this morning (with the new attached app_info.xml) but since then nothing...
So unfortunately I don't have a single SETI unit right now, all clients since 6.3.21 kind of sucks, it doesn't get better :-( In almost every client there is some work fetch problem...
Regarding sharing cores, the problem is we don't know what the CUDA linux app is actually doing while consuming one full core for nothing... When running GPUGRID some months ago, when the app was still consuming half a core for polling the GPU app, there was no performance problem, when running 4+1 rather then 3+1 under Linux... Right now it runs flawlessly in 2+1 or 4+1 mode on my hosts without any difference to 3+1 or 1+1.
edit:
now I got it, sorry, reading an understandig...
My other projects don't have app_infos, so there is nothing to edit :-(
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