Interrupt Service Routine was called with 1.3ms latency

[ddcjz]

Our driver called the following API to install interrupt handler:

viStatus = viInstallHandler(aSession, VI_EVENT_PXI_INTR, pfRoutine, (ViAddr)parameter);

With the help of a PCI analyzer, I noticed that our Interrupt Service Routine pfRoutine was called with 1.3ms delay from when the interrupt was fired. I found that pfRoutine is actually a user space call back function. Our driver is in the User space too.

Is there a way to make a Kernel Interrupt Service call directly? Or we have to re-design our driver in Kernel space. How can we do it?

[rolfk]

Essentially a duplicate post of this: https://forums.ni.com/t5/LabWindows-CVI/How-to-create-a-Kernel-Space-driver/td-p/3634776