title: PCIe latency card to cpu
body: <p>I'm writing a linux app that talks from user space "directly" to a PCIe card, via DMA, without interrupts and kernel.
  My aim is to minimize the data travel time between the card and my app.
  Currently I'm getting latencies of about 800ns, while I was expecting about half that.</p>
  
  <p>Questions:
  1. Is there a way to configure PCIe latency? what are the parameters?
  2. If not, are there motherboards with faster PCIe bus? I looked at few boards but didn't see PCIe latency numbers... what boards are good for that stuff?</p>
  
  <p>Thanks!</p>