Behavior difference between Windows Service and UMDF driver in Modern Standby RRS feed

  • Question

  • In Modern Standby mode, windows service in session 0 shares 1 second / 30 seconds CPU time. Does this apply to UMDF driver? In my opinion, it should be because UMDF driver runs in the process of WUDFHost service, which should follow the same rule. On the other hand, since it is a driver, it may get better execution time when the lower driver starts.

    So what is the correct expectation for UMDF driver in Modern Standby?

    On Windows 8, there was a notion that OS will wake up more often than every 30 seconds for kernel maintenance. Is this true for Windows 10?



    Tuesday, May 30, 2017 3:53 PM

All replies

  • The user mode scheduler was works with threads, not processes or sessions. Modern standby doesn't change that.

    d -- This posting is provided "AS IS" with no warranties, and confers no rights.

    Wednesday, May 31, 2017 2:01 AM
  • Is the thread created in a service different from that in a UMDF driver from scheduling perspective?

    Here is our observation:

    We call WaitForSingleObject with an event handle and timeout value of 5second in both a service and a UMDF driver. We got timeout message every 5 seconds in the UMDF driver but every multiple of 30 seconds in the service. How can I interpret these data?



    Wednesday, May 31, 2017 4:22 PM