Hi William, > > On Tue, Jun 2, 2020 at 12:10 AM Yanqin Wei <yanqin....@arm.com> wrote: > > > > OVS userspace datapath is a program with heavy memory access. It needs > > to load/store a large number of memory, including packet header, > > metadata, EMC/SMC/DPCLS tables and so on. It causes a lot of cache > > line missing and refilling, which has a great impact on flow > > scalability. And in some cases, EMC has a negative impact on the > > overall performance. It is difficult for user to dynamically manage the > enabling of EMC. > > I'm just curious. > Did you do some micro performance benchmark to find out these cache line > issues? Yes, we did some micro benchmarking for packet parsing, EMC and DPCLS. But end2end test is more important because in the fastpath, different data access will affect each other. For example, a large number of EMC table will also impact the access efficiency of metadata or packet header.
> If so, what kind of tool do you use? "perf stat -e" could record many kinds of PMU event. We could use "perf list" to list all events, some of them can be used to measure memory access efficiency (cache miss/refill/evict). > Or do you do it by inspecting the code? Code analysis is also important. We need to analyze the main data accessed in the fast path and their layout. > > Thanks > William _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
