Oliver: I'm not sure there's anything we can do about this, other than for you to increase avg_ncpus to 1.
As you know, GPU jobs are run at normal process priority, so in principle they should preempt CPU jobs, which run at idle priority. However, apparently the Windows CPU scheduler doesn't do this. What's needed is for Microsoft and NVIDIA engineers to see what's going on and fix it. This is not likely to happen since neither of these companies has shown much interest in volunteer computing. -- David On 20-Dec-2010 3:12 AM, Oliver Bock wrote: > Hi everyone, > > We just deployed a new CUDA application (called BRP3) as part of the > einst...@home project. This app roughly up to 75% of a GPU and 3-30% of > a CPU, depending on the GPU model/performance. Thus our scheduler > currently issues these tasks with the following settings: > > hu.avg_ncpus = 0.2 > hu.ncudas = 1 > > Please note that BOINC (e.g. sched/sched_customize) revision 22832 is > used in this case. > > The problem is that with the settings above BOINC starts CUDA tasks in > addition to CPU tasks that already occupy all existing CPU cores. This > means on a system having four CPU cores and two CUDA devices, four CPU > tasks and two CUDA tasks are launched. Although this behavior is > intended, it doesn't really work out for us because the performance of > the CUDA tasks is degraded significantly - GPU usage goes down to less > than 10%, increasing the runtime by the same factor. Although the CUDA > tasks run with slightly higher priority (below normal on Windows) than > the CPU tasks (low on Windows) they are limited by the already > fully-occupied CPU cores which are still required for up to 30% of the > computation. > > Since we couldn't yet release a Linux or Mac OS version we don't know > whether this is a Windows time-slicing issue or not. Are there any other > projects running CUDA tasks in a comparable way? > > The only workaround in sight would be to acquire a full CPU core once > again but that's certainly not ideal. > > Any ideas are welcome! > > > Cheers, > Oliver _______________________________________________ boinc_dev mailing list [email protected] http://lists.ssl.berkeley.edu/mailman/listinfo/boinc_dev To unsubscribe, visit the above URL and (near bottom of page) enter your email address.
