On Wed, Jan 24, 2024 at 2:29 AM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote: > > On 1/17/24 10:56 PM, Amery Hung wrote: > > tc_sch_fq.bpf.c > > A simple bpf fair queueing (fq) qdisc that gives each flow a euqal chance > > to transmit data. The qdisc respects the timestamp in a skb set by an > > clsact rate limiter. It can also inform the rate limiter about packet drop > > when enabled to adjust timestamps. The implementation does not prevent hash > > collision of flows nor does it recycle flows. > > > > tc_sch_fq.c > > A user space program to load and attach the eBPF-based fq qdisc, which > > by default add the bpf fq to the loopback device, but can also add to other > > dev and class with '-d' and '-p' options. > > > > To test the bpf fq qdisc with the EDT rate limiter: > > $ tc qdisc add dev lo clsact > > $ tc filter add dev lo egress bpf obj tc_clsact_edt.bpf.o sec classifier > > $ ./tc_sch_fq -s > > Would be nice if you also include a performance comparison (did you do > production tests with it?) with side-by-side to native fq and if you see > a delta elaborate on what would be needed to address it. I did a simple test by adding a fq to the loopback device and then sending a single stream traffic via iperf. The bpf implementation of fq achieves 90% throughput compared with the native one. I think the overhead mainly comes from allocating bpf objects (struct skb_node) to store skb kptrs. This part can be removed if bpf list/rbtree recognizes skb->list/rbnode. On the kfunc implementation side, I think we can do it by saving struct bpf_rb_node_kern into skb->rb_node and skb->cb. I haven't looked into the verifier to see what needs to be done. I will move the test cases from samples to selftests and include more testing in the next patchset. > > > Signed-off-by: Amery Hung <amery.hung@xxxxxxxxxxxxx> > > --- > > samples/bpf/Makefile | 8 +- > > samples/bpf/bpf_experimental.h | 134 +++++++ > > samples/bpf/tc_clsact_edt.bpf.c | 103 +++++ > > samples/bpf/tc_sch_fq.bpf.c | 666 ++++++++++++++++++++++++++++++++ > > samples/bpf/tc_sch_fq.c | 321 +++++++++++++++ > > 5 files changed, 1231 insertions(+), 1 deletion(-) > > create mode 100644 samples/bpf/bpf_experimental.h > > create mode 100644 samples/bpf/tc_clsact_edt.bpf.c > > create mode 100644 samples/bpf/tc_sch_fq.bpf.c > > create mode 100644 samples/bpf/tc_sch_fq.c
