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Author	SHA1	Message	Date
brakmo	d58c6f7212	bpf: Add more stats to HBM Adds more stats to HBM, including average cwnd and rtt of all TCP flows, percents of packets that are ecn ce marked and distribution of return values. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>	2019-05-31 16:41:29 -07:00
brakmo	ffd81558d5	bpf: Add cn support to hbm_out_kern.c Update hbm_out_kern.c to support returning cn notifications. Also updates relevant files to allow disabling cn notifications. Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>	2019-05-31 16:41:29 -07:00
brakmo	187d0738ff	bpf: Sample HBM BPF program to limit egress bw A cgroup skb BPF program to limit cgroup output bandwidth. It uses a modified virtual token bucket queue to limit average egress bandwidth. The implementation uses credits instead of tokens. Negative credits imply that queueing would have happened (this is a virtual queue, so no queueing is done by it. However, queueing may occur at the actual qdisc (which is not used for rate limiting). This implementation uses 3 thresholds, one to start marking packets and the other two to drop packets: CREDIT - <--------------------------\|------------------------> + \| \| \| 0 \| Large pkt \| \| drop thresh \| Small pkt drop Mark threshold thresh The effect of marking depends on the type of packet: a) If the packet is ECN enabled, then the packet is ECN ce marked. The current mark threshold is tuned for DCTCP. c) Else, it is dropped if it is a large packet. If the credit is below the drop threshold, the packet is dropped. Note that dropping a packet through the BPF program does not trigger CWR (Congestion Window Reduction) in TCP packets. A future patch will add support for triggering CWR. This BPF program actually uses 2 drop thresholds, one threshold for larger packets (>= 120 bytes) and another for smaller packets. This protects smaller packets such as SYNs, ACKs, etc. The default bandwidth limit is set at 1Gbps but this can be changed by a user program through a shared BPF map. In addition, by default this BPF program does not limit connections using loopback. This behavior can be overwritten by the user program. There is also an option to calculate some statistics, such as percent of packets marked or dropped, which the user program can access. A latter patch provides such a program (hbm.c) Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>	2019-03-02 10:48:27 -08:00

Author

SHA1

Message

Date

brakmo

d58c6f7212

bpf: Add more stats to HBM

Adds more stats to HBM, including average cwnd and rtt of all TCP
flows, percents of packets that are ecn ce marked and distribution
of return values.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2019-05-31 16:41:29 -07:00

brakmo

ffd81558d5

bpf: Add cn support to hbm_out_kern.c

Update hbm_out_kern.c to support returning cn notifications.
Also updates relevant files to allow disabling cn notifications.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2019-05-31 16:41:29 -07:00

brakmo

187d0738ff

bpf: Sample HBM BPF program to limit egress bw

A cgroup skb BPF program to limit cgroup output bandwidth.
It uses a modified virtual token bucket queue to limit average
egress bandwidth. The implementation uses credits instead of tokens.
Negative credits imply that queueing would have happened (this is
a virtual queue, so no queueing is done by it. However, queueing may
occur at the actual qdisc (which is not used for rate limiting).

This implementation uses 3 thresholds, one to start marking packets and
the other two to drop packets:
                                 CREDIT
       - <--------------------------|------------------------> +
             |    |          |      0
             |  Large pkt    |
             |  drop thresh  |
  Small pkt drop             Mark threshold
      thresh

The effect of marking depends on the type of packet:
a) If the packet is ECN enabled, then the packet is ECN ce marked.
   The current mark threshold is tuned for DCTCP.
c) Else, it is dropped if it is a large packet.

If the credit is below the drop threshold, the packet is dropped.
Note that dropping a packet through the BPF program does not trigger CWR
(Congestion Window Reduction) in TCP packets. A future patch will add
support for triggering CWR.

This BPF program actually uses 2 drop thresholds, one threshold
for larger packets (>= 120 bytes) and another for smaller packets. This
protects smaller packets such as SYNs, ACKs, etc.

The default bandwidth limit is set at 1Gbps but this can be changed by
a user program through a shared BPF map. In addition, by default this BPF
program does not limit connections using loopback. This behavior can be
overwritten by the user program. There is also an option to calculate
some statistics, such as percent of packets marked or dropped, which
the user program can access.

A latter patch provides such a program (hbm.c)

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2019-03-02 10:48:27 -08:00

3 Commits