On Thu, Nov 24, 2016 at 02:01:41AM -0500, Kenneth Adam Miller wrote:
Hello,
I have a scheduler issue in two different respects:
1) I have a process that is supposed to tight loop, and it is being given very very little time on the system. I don't want that - I want those who would use the processor to be given the resources to run as fast as they each can.
What is causing it to give up its timeslice? Is it waiting for I/O? Doing something else to sleep?
2) I am seeing with perf that the maximum overhead at each section does not sum up to be more than 15 percent. Total, probably something like 18% of cpu time is used, and my binary has rocketed in slowness from about 2 seconds or less total to several minutes.
What changed to make things slower? Did you change kernel versions or did you change something in your userspace program?
I think that the linux scheduler isn't scheduling it, because this process is just some unit tests that double as benchmarks in that they shm_open a file and write into it with memcpy's.
Are you sure that I/O isn't happening here like through swap or something else? What does perf say is taking all of your time? thanks, greg k-h