I was so preoccupied with cudaThreadSynchronize to be a blocking operation that i attributed the reported high cpu usage to display update interference from the kernels. It is sad to learn your cpu has spent the last months in a spinlock 90% of the time. Sleeping is now performed automatically by measuring the time between guessed kernel time and actual kernel time and adapting the guessed kernel time accordingly. Also there was a minor error that caused the program to compute wrong chains that would never end if you accidently wrote --condition rounds::rounds=32 instead of --condition rounds:rounds=32. I highly recommend you update to either the current svn or the binaries to not waste energy. Also as an extra precaution run make test and make test2 and write to a new table file after the update (e.g. --consume file:prefix=data23:append). You would not want to let murphy creep in.
Regards, Sascha > Hi, > > before letting this tool run as a background service on my 4 GPU rig I > would very much like to lower the use of CPU resources, as this > contribute a significant amount to power consumption and heat > production. > > Generally when you run a CUDA kernel that has a predictable run time, > it is a good idea to put the CPU into sleep state for a time that is > just a little shorter than the expected kernel run time. > > Now I do not know what other jobs the CPU has in the TMTO code base, > but if it is mostly busy-waiting (polling) for the results of the CUDA > kernel, inserting a sleep statement might be an excellent idea. > > You could for example perform a kernal execution time measurement for > example on every 100th kernel call, and in the 99 iterations inbetween > you could sleep the CPU for 90% of the previously measured time (just > after launching the kernel). The CPU will wake up just in time to > perform the busy wait for the kernel to actually finish. Performance > impact should be nil. > > A CPU consumption of 5-10% per running TMTO instance would be very > acceptable to me, the current 82% are not. > > Christian > _______________________________________________ > A51 mailing list > [email protected] > http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51 > ________________________________________________________________ Neu: WEB.DE Doppel-FLAT mit Internet-Flatrate + Telefon-Flatrate für nur 19,99 Euro/mtl.!* http://produkte.web.de/go/02/ _______________________________________________ A51 mailing list [email protected] http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51
