From: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx> Date: Sat, 4 Feb 2017 18:05:05 +0100 > This is the first set which begins to deal with the bad bridge cache > access patterns. The first patch rearranges the bridge and port structs > a little so the frequently (and closely) accessed members are in the same > cache line. The second patch then moves the garbage collection to a > workqueue trying to improve system responsiveness under load (many fdbs) > and more importantly removes the need to check if the matched entry is > expired in __br_fdb_get which was a major source of false-sharing. > The third patch is a preparation for the final one which > If properly configured, i.e. ports bound to CPUs (thus updating "updated" > locally) then the bridge's HitM goes from 100% to 0%, but even without > binding we get a win because previously every lookup that iterated over > the hash chain caused false-sharing due to the first cache line being > used for both mac/vid and used/updated fields. > > Some results from tests I've run: > (note that these were run in good conditions for the baseline, everything > ran on a single NUMA node and there were only 3 fdbs) > > 1. baseline > 100% Load HitM on the fdbs (between everyone who has done lookups and hit > one of the 3 hash chains of the communicating > src/dst fdbs) > Overall 5.06% Load HitM for the bridge, first place in the list > > 2. patched & ports bound to CPUs > 0% Local load HitM, bridge is not even in the c2c report list > Also there's 3% consistent improvement in netperf tests. Looks great, series applied, thanks!
