I need to understand the below scenario
On Sql server 2014 with compatibility mode of 2008R2, having 80 logical processors with 20 distributed amongst 4 numa nodes. I. E numa node 1 has 0-19 , numa node 2 has 20-39 and so on.
While checking the cpu usage, we believe workload should be equally distributed amongst all of them. Sometime i see like equal distribution to some extent amongst all numa nodes to their processors.
But some time lets say during maintainence window like backup or index main jobs or runs, why is that lets say numa node 0 and 1 will not have any equal usage compares to 2 and 3 or vice versa. As far as i think it should be equally distributed.
Note we are running enterprise core edition.
Is this expected or something missing in the settings of these cores?
Update@ As said by Randolph, some process can go single threaded, i got it, but why out of the 80 they are using 80-90 % of cpu on few processors while other sitting idle. Cant the workload be equally divided when say there are 10-15 with high usage showing while remaining 50 odd processors sitting idle