Performance of CPU thread downgraded

[alexyangfox]

Hi, pitzer.
I have tested your codes(cuda-based version) in Ubuntu 14.04 with cuda 7.5
I found the CPU utilization is very high.
Most of the Time, it is 100 % .
This would prevented my machine from doing any other CPU intensive jobs.

I found that this is an issue with the cuda runtime library.
The asynchronous Memcpy need occasionally call clock_gettime to query the states of the operation.
And I googled this: link
The link above says: cudaDeviceScheduleBlockingSync turned out to be a solution.

Regards.