On Sun, May 29, 2016 at 06:38:41PM -0400, Doug Ledford wrote: > So I've been busy with kernel stuff, but I don't really like this patch. > I'm not really enamored with the entire poll_ex API. You should really read the whole prior discussion > First, I don't like the start_poll/poll/end_poll setup. I would rather > we do something like using refcounting on the WCs. Maybe something like > returning an array of pointers to WCs where each WC already has a > ref Refs? Yuk. That doesn't fit the typical use model, and refs involve more expensive locking per wc. > When a cq is created by the driver, it is responsible for filling out > the offsets array (can be static if your driver only has one CQE > format, *shrug* Careful benchmarking would have to prove if this is better or not. Based on Yishai's comments I expect it is not better, since I expect an offsets array to perform worse than the original bitmask thing. Yishai's said this benchmarked better than the bitmask and equal to or better than today's versions.. This is a whole picture optimization and the user side is only one part of the equation - the function pointer scheme is also optimizing the driver path quite heavily, which is why it is showing positively in benchmarks. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
