And refactor the code to avoid unneeded initialization to reduce overhead of per-packet processing. ipfw(4) can be invoked by pfil(9) framework for each packet several times. Each call uses on-stack variable of type struct ip_fw_args to keep the state of ipfw(4) processing. Currently this variable has 240 bytes size on amd64. Each time ipfw(4) does bzero() on it, and then it initializes some fields. glebius@ has reported that they at Netflix discovered, that initialization of this variable produces significant overhead on packet processing. After patching I managed to increase performance of packet processing on simple routing with ipfw(4) firewalling to about 11% from 9.8Mpps up to 11Mpps (Xeon E5-2660 v4@ + Mellanox 100G card). Introduced new field flags, it is used to keep track of what fields was initialized. Some fields were moved into the anonymous union, to reduce the size. They all are mutually exclusive. dummypar field was unused, and therefore it is removed. The hopstore6 field type was changed from sockaddr_in6 to a bit smaller struct ip_fw_nh6. And now the size of struct ip_fw_args is 128 bytes. ipfw_chk() was modified to properly handle ip_fw_args.flags instead of rely on checking for NULL pointers. Reviewed by: gallatin Obtained from: Yandex LLC MFC after: 1 month Sponsored by: Yandex LLC Differential Revision: https://reviews.freebsd.org/D18690 |
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