To ensure the least amount of data loss over USB elevating the thread priority is the best(only?) way we have found to do this. As far as I know root privilege is required for this on Linux (not the case on Windows).
With multiple devices actively making measurements, you will experience data loss if this isn’t done.
I had another customer do a bit of testing with niceness levels and it never resulted in an adequate solution. (His processing would still swamp the CPU and cause data loss events while I/Q streaming despite using niceness levels and despite pulling his processing out into separate processes.)
Below is the snippet we use to do this. You are free to play around and determine if one of your solutions will work. The result of the pthread_setschedparam() will indicate when it fails due to privilege issues. We don’t push this status back out to the user, but I have a request to in a future update. That way the user can ensure the API is setting the proper priority. The API doesn’t check (or care) if it fails at the moment.
void ElevateThreadPriority(std::thread &t)
{
pthread_t this_thread = (pthread_t)t.native_handle();
struct sched_param params;
int tp = 10;
params.sched_priority = tp;
int res = pthread_setschedparam(this_thread, SCHED_FIFO, ¶ms);
}
