Multiqueue support for bpf

[Luigi Rizzo]

On Mon, Jul 1, 2013 at 2:01 PM, Takuya ASADA <syuu at dokukino.com> wrote:

> Hi all,
>
> I'd like to propose multiqueue support for bpf.
> It's result of GSoC'11, and proposed on freebsd-net at Aug.2011 but not yet
> merged:
>
> http://www.google-melange.com/gsoc/proposal/review/google/gsoc2011/syuu1228/1
> http://lists.freebsd.org/pipermail/freebsd-net/2011-August/029585.html


Do you have an updated URL for the diffs ? The link below from your
original message
seems not working now (NXDOMAIN)

http://www.dokukino.com/mq_bpf_20110813.diff

Specifically, I am curious about the type of mbuf changes, because there
are many
pending changes to the mbufs we'd like to have (such as some local
room/leading space
to store metadata instead of using expensive mtags), and in the interest of
API stability
we should try and make those changes at once.

ifnet changes are also a concern but less important (they are only a
compile time
issue, whereas mbuf changes potentially have an impact on runtime)

cheers
luigi



>
> The objectives of the patch is to support multiqueue NICs on BPF, and
> provide interfaces for multithreaded packet processing using BPF.
> To get optimal performance and to reduce lock contention, multiqueue BPF
> provides a feature to specify hardware queues.
> Following is basic usage of multiqueue BPF:
>
> void *bpf_thread(void *arg) {
>     cpu = (int)arg;
>     CPU_ZERO(&cpuset);
>     CPU_SET(cpu, &cpuset);
>     cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID, -1, sizeof(cpuset),
> &cpuset);
>     fd = open("/dev/bpf0", O_RDWR);
>     ioctl(fd, BIOCSTRXQMASK, &cpu);
>     ioctl(fd, BIOCSTTXQMASK, &cpu);
>     /* actual works */
> }
>
> int main(void)
> {
>     for (i = 0; i < maxcpus; i++)
>         pthread_create(&threads[i], NULL, bpf_thread, (void *)i);
>     for (i = 0; i < maxcpus; i++)
>         pthread_join(&threads[i], NULL);
> }
>
> In this example, threads[n] bind to CPUn, receives packets from rxqueue n
> and txqueue n.
>
> To implement it, the patch modifies bpf_*tap*() and extends struct ifnet,
> struct mbuf to notify hardware queue information.
>
> The changes are in this branch:
> http://svnweb.freebsd.org/base/user/syuu/mq_bpf/
>
> API descriptions and benchmark results are on previous post:
> http://lists.freebsd.org/pipermail/freebsd-net/2011-August/029585.html
>
> Benchmark program is on this repository:
> https://github.com/syuu1228/mq_bpf_test
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>



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 Prof. Luigi RIZZO, rizzo at iet.unipi.it  . Dip. di Ing. dell'Informazione
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