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Entry  13 Feb 2020, Marius Koeppel, Forum, Writting Midas Events via FPGAs 
    Reply  13 Feb 2020, Stefan Ritt, Forum, Writting Midas Events via FPGAs 
       Reply  14 Feb 2020, Konrad Briggl, Forum, Writting Midas Events via FPGAs 
          Reply  14 Feb 2020, Stefan Ritt, Forum, Writting Midas Events via FPGAs 
             Reply  20 Feb 2020, Konstantin Olchanski, Forum, Writting Midas Events via FPGAs 
                Reply  20 Feb 2020, Marius Koeppel, Forum, Writting Midas Events via FPGAs 
                   Reply  20 Feb 2020, Stefan Ritt, Forum, Writting Midas Events via FPGAs 
                      Reply  21 Feb 2020, Konstantin Olchanski, Forum, Writting Midas Events via FPGAs 
                         Reply  21 Feb 2020, Stefan Ritt, Forum, Writting Midas Events via FPGAs 
                   Reply  21 Feb 2020, Konstantin Olchanski, Forum, Writting Midas Events via FPGAs 
Message ID: 1844     Entry time: 21 Feb 2020     In reply to: 1841     Reply to this: 1846
Author: Konstantin Olchanski 
Topic: Forum 
Subject: Writting Midas Events via FPGAs 
> We also agree and found the problem now.

Good. what was wrong?

> - Own DMA engine since we are doing burst writing DMA with PCIe 3.0. 
> - Own device driver

Scary stuff.

> - no interrupts 

Right. Best I can tell, interrupts no longer useful in Linux - interrupt handler cannot do any real work, has to hand off to a kernel thread, resulting
in so much latency and overhead that one might as well poll for the data... And for DMA data transfers, the data rate is well known,
so easy to predict how long the DMA will run for and sleep for that amount of time instead of waiting for an interrupt.

K.O.
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