How would %privilege time of sqlsvr instance indicate cpu consumption of other processes?

Question

I am looking at msdn doc to monitor cpu.

Link: https://learn.microsoft.com/en-us/troubleshoot/sql/performance/troubleshoot-high-cpu-usage-issues#step-1-verify-that-sql-server-is-causing-high-cpu-usage

It says I need to capture the %user time and %privileged time for sqlsvr instance.

Then it goes to say high %user time means sqlsvr is keeping cpu busy. Where as high %privileges time means other processes or anti-virus is keeping the cpu busy.

My question is - how would %privilege time of sqvsvr instance indicate cpu consumption of other processes?

Answer 1

Privileged time is when a process thread is running in the kernel. All of the SQL Server code, like most applications, runs in user-mode, not kernel mode.

It's not other processes, but drivers or products that insert themselves into the storage driver stacks (particularly anti-virus or storage solution filter drivers) that are the common cause of high privileged time.