Hello,
I've recently virtualized a machine used for CNC milling. It drove the end equipment using a parallel port. I have installed a PCI parallel port card in the host, and configured ESXi (6.0) to pass it through to the guest. When I run the mill, it works, but only at a fraction (1/5 as it turns out) of the speed it should. When I run a parallel port driver test it shows that the CNC software (mach3) can only pulse the parallel port 5k/sec, and it requires at least 25k pulses/sec.
I have verified the 5k/sec pulse limit using three different PCI cards, so it seems clear that this is an issue/bottleneck with ESXi. So, my questions are:
1) What exactly is this 5k limit? Is it a polling interval? Interrupt timer?
2) Is there a way to configure the host or guest to increase the parallel port speed?
Thanks for your help.