ive heard on bsdcan this year that some patches exist to add hwcsum offloading to netmap, hope to see it chelsio at least
-- ./andy 14.06.2016, 12:15, "Dominik Schoeffmann" <schoe...@in.tum.de>: > Dear Netmap Developers, > > during the course of my bachelor's thesis, I modified a packet generator > called MoonGen [1] in order to utilize netmap. > One key component was to flexibly offload checksums for different kinds > of packets (IPv4, UDP, TCP). > The ixgbe netmap patch was modified [2] in order to construct context > descriptors and suitable data descriptors. This is implemented in less > than 250 LoC (including pseudo-header calculations). > The man page states, that checksum offloading is available via ethtool, > although a solution inside the netmap API might be a cleaner way for > applications to actually use these features. > Attached is a graph showing the performance implication of using > offloading in the current implementation. > As can be seen, offloading has only a minor impact. > When regarding this data (and comparing it to other frameworks), please > keep in mind, that internally a lot of per-packet effort is needed due > to the software architecture of the packet generator. > > The question being: > Would it not make sense to include checksum offloading inside of netmap > in order to accomodate applications operating on layer 3 and above? > As these programs need to calculate the checksums in software, it would > be just as fast to move these calculations to the kernel for NICs > without checksum offloading support (and the kernel would act as a library). > The problem which currently is imposed by the fact, that netmap exports > the complete ring, is that context descriptors disrupt the data > descriptors, which is unpleasant for the application. > But you may find the data interesting nevertheless. > > Best Regards, > Dominik Schoeffmann > > [1] https://github.com/dschoeffm/MoonGen/tree/netmap > [2] https://github.com/dschoeffm/netmap/tree/mg-chksum-offloading _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
