• Nikolay Aleksandrov's avatar
    net: bridge: use rhashtable for fdbs · eb793583
    Nikolay Aleksandrov authored
    Before this patch the bridge used a fixed 256 element hash table which
    was fine for small use cases (in my tests it starts to degrade
    above 1000 entries), but it wasn't enough for medium or large
    scale deployments. Modern setups have thousands of participants in a
    single bridge, even only enabling vlans and adding a few thousand vlan
    entries will cause a few thousand fdbs to be automatically inserted per
    participating port. So we need to scale the fdb table considerably to
    cope with modern workloads, and this patch converts it to use a
    rhashtable for its operations thus improving the bridge scalability.
    Tests show the following results (10 runs each), at up to 1000 entries
    rhashtable is ~3% slower, at 2000 rhashtable is 30% faster, at 3000 it
    is 2 times faster and at 30000 it is 50 times faster.
    Obviously this happens because of the properties of the two constructs
    and is expected, rhashtable keeps pretty much a constant time even with
    10000000 entries (tested), while the fixed hash table struggles
    considerably even above 10000.
    As a side effect this also reduces the net_bridge struct size from 3248
    bytes to 1344 bytes. Also note that the key struct is 8 bytes.
    Signed-off-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    eb793583
br_private.h 32.1 KB