> The graphs are up now. The best driver measured so far is
> Robert's change to reinstate irq-disable-on-poll +
> reduce-pci-traffic, with XsumRX turned off. I'm currently
> measuring to see if it still has an advantage with
> checksumming turned on.
Very good. Jeff has the patch for -k2 which should be equivalent to
Robert, please post your -ro3 changes - I can't find them.
BTW, the things that changed from 4.4.19-k3 to 5.0.43-k2 that may
account for the improvements are:
o eliminate the modulus operator for ring index wrapping
o single read of ICR (Interrupt Cause Register) in e1000_intr
o dynamic ITR (Interrupt Throttle Rate) algorithm for 82545/6
Sum of many second-order improvements add up. We'll take all we can
> Scott, your bugfix of removing the while() from e1000_clean()
> puts the original 5.0.43-k1 driver from 2.5.66 back in the
> running. It no longer suffers from watchdog timeouts, and
> doesn't degrade under high load. It still scores lowest,
> though. I've seen that the max-pps-ceiling visible in these
> graphs is highly sensitive to CPU load, so I'd guess that the
> sf1 test lost solely because of the overhead of still running
> the irq handler once in a while.
Ok, that settles that. Thanks for re-running the tests.
I'm pretty happy with this NAPI code for e1000. Next step is to get
some more generic QA testing with NAPI and then port back to 2.4.x.