[openib-general] [PATCH/RFC 1/2] IB: Return "maybe_missed_event" hint from ib_req_notify_cq()

[Roland Dreier]

 > Thanks. The touch test results are not good. This NAPI patch induces huge
 > latency for ehca driver scaling code, the throughput performance is not
 > good. (I am not fully conviced the huge latency is because of raising NAPI
 > in thread context.) Then I tried ehca no scaling driver, the latency looks
 > good, but the throughtput is still a problem. We are working on these
 > issues. Hopefully we can get the answer soon.

Hmm, the results with "scaling" on are not that unexpected, since the
idea of scheduling a thread round-robin (to kill all cache locality)
is pretty dubious anyway.

I would like to understand why there's a throughput difference with
scaling turned off, since the NAPI code doesn't change the interrupt
handling all that much, and should lower the CPU usage if anything.
Does changing the netdev weight value affect anything?

 - R.