Wait functions listed high in CPU sampling
Hi,
I was having troubles explaining to a customer why in CPU sampling he saw the wait methods as the highest CPU execution time. Can you assist in providing a clear explanation ?
Thanks,
Gil.
Actually it does, but that is not the point.
CPU sampling does not only sample how much CPU is consumed, it samples what threads do with the CPU. When a thread waits for a long time, thus does not really use the CPU (again not completely true anyhow) than we also see this and mark it accordingly. In the same way we see Sync or GC time, because we know that the thread is syncing or blocked by GC during that time.
You should be able to get context of that wait method in the CPU Sample (i.e. what called it, such as an LDAP authentication or DB socketRead0 request), otherwise you can just open the Methods Hotspots dashlet and search for the wait method to see the context in which it is called.
