> Processing the flag IB_CQ_REPORT_MISSED_EVENTS causes several IB
> drivers to lock and unlock a spinlock. Full-speed SRP I/O can cause
> this operation to be invoked more than 100.000 times a second, so the
> flag IB_CQ_REPORT_MISSED_EVENTS will have a small but measurable
> impact on SRP I/O performance.
It seems the only driver where that happens is ehca. But on the other
hand, for mthca/mlx4 it avoids doing something like:
cq event:
request notify <-- CQ is not empty, another event queued
drain CQ
cq event:
request notify
drain already empty CQ
ie the overhead saved here looks a lot more.
--
Roland Dreier <[email protected]> || For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/index.html
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