When is more than one PIT needed?

Hello,

I need to be able to put a process to sleep for 100-1000 microseconds (until now, I've been using a generic Linux kernel on a low-voltage x86 CPU). AFAIU, the x86 platform comes with several timers[*] and I had hoped one of them would prove useful in my situation.

At some point, I was convinced that the simplest solution would be to purchase a PCI card with multiple Programmable Interval Timers, such as ADLINK's PCI-8554:

Then I ran into the relatively new hrtimers infrastructure[*] which seems to let me do what I need. (I'm not sure how, though.)

I'm confused. It seems a generic Linux kernel can indeed provide high-resolution timers without any additionnal hardware.

Then when is a card with multiple PITs needed? Have any of you ever been in a situation where software came up short, and the multiple PITs were mandatory? What are the typical uses of such a card?

Regards.