Add tbf (token bucket filter) qdisc to support egress traffic shaping / rate limiting#13104
Add tbf (token bucket filter) qdisc to support egress traffic shaping / rate limiting#13104benldrmn wants to merge 1 commit into
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Implements a single-rate TBF qdisc modeled on Linux's net/sched/sch_tbf.c and exposes it via --qdisc=tbf, with required --qdisc-tbf-rate and --qdisc-tbf-burst flags. OCI annotations can lower the configured rate and burst ceilings but not raise them without --allow-flag-override. The fifo qdisc's circular packet-buffer list moves into a shared pkg/tcpip/link/qdisc package so both qdiscs share one implementation. Loopback and ingress traffic are not shaped.
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Can you show benchmark results? |
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@EtiennePerot sure. Used iperf client inside the sandbox and the server outside (in the same kind cluster), host gso enabled, qdisc-tbf-rate = 100000000000 (100 Gbps), qdisc-tbf-burst = 134217728 (128 MiB), 20 iterations for each setup:
similar, but 12 iterations per setup (building up to 32 concurrent streams):
bounding the client pace to more realistic numbers - iperf client is sending in
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| // psched_ratecfg_precompute__ in net/sched/sch_generic.c. | ||
| func len2TimeNS(rate uint64, len uint32) uint64 { | ||
| const nsecPerSec = 1000000000 | ||
| return uint64(len) * nsecPerSec / rate |
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I can get rid of this division by precalculating mul and shift params in New, for the "cost" of complicating the code a bit (the precalculation and storing those less intuitive mul and shift for later use in len2TimeNS)
| @@ -0,0 +1,109 @@ | |||
| // Copyright 2022 The gVisor Authors. | |||
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I just moved it from the fifo package so I can reuse the logic in tbf, I don't know why git recognizes it as "new" code. The diff is basically exporting the relevant symbols and adding a peek method
| // +checklocksignore: we don't have to hold locks during initialization. | ||
| func New(lower stack.LinkEndpoint, clock tcpip.Clock, rate uint64, burst, queueLen uint32) (stack.QueueingDiscipline, error) { | ||
| if rate == 0 { | ||
| return nil, fmt.Errorf("qdisc=tbf requires setting qdisc-tbf-rate") |
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should I use some tcpip error in this file instead of returning fmt.Errorfs?
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resolves the egress part of #11109.
AI usage disclosure: used ai to help me generate some tests and cleanups after the manual implementation I did by hand modeled after
linux/net/sched/sch_tbf.cTBF implementation. Also used it in guided documentation writing. I understand every line of code written and wrote the core logic manually, and happy to answer questions / revisit parts of the implementation as necessary.Also tested and benchmarked manually against a local Kubernetes kind cluster to ensure it resolves isola-run/isola#290