On 2024-10-09 11:21, Pedro Tammela wrote: > On 09/10/2024 13:55, Mina Almasry wrote: >> [...] >> >> If not, I would like to see a comparison between TCP RX zerocopy and >> this new io-uring zerocopy. For Google for example we use the TCP RX >> zerocopy, I would like to see perf numbers possibly motivating us to >> move to this new thing. >> >> [1] https://lwn.net/Articles/752046/ >> > > Hi! > > From my own testing, the TCP RX Zerocopy is quite heavy on the page unmapping side. Since the io_uring implementation is expected to be lighter (see patch 11), I would expect a simple comparison to show better numbers for io_uring. Hi Pedro, I will add TCP_ZEROCOPY_RECEIVE to kperf and compare in the next patchset. > > To be fair to the existing implementation, it would then be needed to be paired with some 'real' computation, but that varies a lot. As we presented in netdevconf this year, HW-GRO eventually was the best option for us (no app changes, etc...) but still a case by case decision. Why is there a need to add some computation to the benchmarks? A benchmark is meant to be just that - a simple comparison that just looks at the overheads of the stack. Real workloads are complex, I don't see this feature as a universal win in all cases, but very workload and userspace architecture dependent. As for HW-GRO, whynotboth.jpg?
