- 22 Sep, 2016 8 commits
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David S. Miller authored
Shmulik Ladkani says: ==================== act_vlan: Introduce TCA_VLAN_ACT_MODIFY vlan action TCA_VLAN_ACT_MODIFY allows one to change an existing tag. It accepts same attributes as TCA_VLAN_ACT_PUSH (protocol, id, priority). If packet is vlan tagged, then the tag gets overwritten according to user specified attributes. For example, this allows user to replace a tag's vid while preserving its priority bits (as opposed to "action vlan pop pipe action vlan push"). ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
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Shmulik Ladkani authored
TCA_VLAN_ACT_MODIFY allows one to change an existing tag. It accepts same attributes as TCA_VLAN_ACT_PUSH (protocol, id, priority). If packet is vlan tagged, then the tag gets overwritten according to user specified attributes. For example, this allows user to replace a tag's vid while preserving its priority bits (as opposed to "action vlan pop pipe action vlan push"). Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Shmulik Ladkani authored
This exports the functionality of extracting the tag from the payload, without moving next vlan tag into hw accel tag. Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller authored
Tariq Toukan says: ==================== mlx4 misc cleanups and improvements This patchset contains some cleanups and improvements from the team to the mlx4 Eth and core drivers. Series generated against net-next commit: 5a7a5555 'net sched: stylistic cleanups' ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
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Jack Morgenstein authored
When switching from polling-based fw commands to event-based fw commands, there is a race condition which could cause a fw command in another task to hang: that task will keep waiting for the polling sempahore, but may never be able to acquire it. This is due to mlx4_cmd_use_events, which "down"s the sempahore back to 0. During driver initialization, this is not a problem, since no other tasks which invoke FW commands are active. However, there is a problem if the driver switches to polling mode and then back to event mode during normal operation. The "test_interrupts" feature does exactly that. Running "ethtool -t <eth device> offline" causes the PF driver to temporarily switch to polling mode, and then back to event mode. (Note that for VF drivers, such switching is not performed). Fix this by adding a read-write semaphore for protection when switching between modes. Fixes: 225c7b1f ("IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters") Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il> Signed-off-by: Matan Barak <matanb@mellanox.com> Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Leon Romanovsky authored
Radix tree lookup can be performed without locking. Fixes: 225c7b1f ("IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters") Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Suggested-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Kamal Heib authored
Use tabs instead of spaces before if statement, no functional change. Fixes: e7c1c2c4 ("mlx4_en: Added self diagnostics test implementation") Signed-off-by: Kamal Heib <kamalh@mellanox.com> Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Tariq Toukan authored
Add likely/unlikely hints to improve branch predictions in the RX data-path. Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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- 21 Sep, 2016 32 commits
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David S. Miller authored
Jakub Kicinski says: ==================== BPF hardware offload (cls_bpf for now) Rebased and improved. v7: - fix patch 4. v6 (patch 8 only): - explicitly check for registers >= MAX_BPF_REG; - fix leaky error path. v5: - fix names of guard defines in bpf_verfier.h. v4: - rename parser -> analyzer; - reorganize the analyzer patches a bit; - use bitfield.h directly. --- merge blurb: In the last year a lot of progress have been made on offloading simpler TC classifiers. There is also growing interest in using BPF for generic high-speed packet processing in the kernel. It seems beneficial to tie those two trends together and think about hardware offloads of BPF programs. This patch set presents such offload to Netronome smart NICs. cls_bpf is extended with hardware offload capabilities and NFP driver gets a JIT translator which in presence of capable firmware can be used to offload the BPF program onto the card. BPF JIT implementation is not 100% complete (e.g. missing instructions) but it is functional. Encouragingly it should be possible to offload most (if not all) advanced BPF features onto the NIC - including packet modification, maps, tunnel encap/decap etc. Example of basic tests I used: __section_cls_entry int cls_entry(struct __sk_buff *skb) { if (load_byte(skb, 0) != 0x0) return 0; if (load_byte(skb, 4) != 0x1) return 0; skb->mark = 0xcafe; if (load_byte(skb, 50) != 0xff) return 0; return ~0U; } Above code can be compiled with Clang and loaded like this: ethtool -K p1p1 hw-tc-offload on tc qdisc add dev p1p1 ingress tc filter add dev p1p1 parent ffff: bpf obj prog.o action drop This set implements the basic transparent offload, the skip_{sw,hw} flags and reporting statistics for cls_bpf. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Add offload of TC in direct action mode. We just need to provide appropriate checks in the verifier and a new outro block to translate the exit codes to what data path expects Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Data path has redirect support so expressing redirect to the port frame came from is a trivial matter of setting the right result code. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Implement .stats_update() callback. The implementation is generic and can be reused by other simple actions if needed. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Add missing ABI defines and eBPF instructions to allow mark to be passed on and extend prepend parsing on the RX path to pick it up from packet metadata. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Periodically poll stats and call into offloaded actions to update them. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Call into offloaded filters to update stats. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Add hardware bpf offload on our smart NICs. Detect if capable firmware is loaded and use it to load the code JITed with just added translator onto programmable engines. This commit only supports offloading cls_bpf in legacy mode (non-direct action). Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Add translator for JITing eBPF to operations which can be executed on NFP's programmable engines. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
When running as parser interpret BPF_LD | BPF_IMM | BPF_DW instructions as loading CONST_IMM with the value stored in imm. The verifier will continue not recognizing those due to concerns about search space/program complexity increase. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Advanced JIT compilers and translators may want to use eBPF verifier as a base for parsers or to perform custom checks and validations. Add ability for external users to invoke the verifier and provide callbacks to be invoked for every intruction checked. For now only add most basic callback for per-instruction pre-interpretation checks is added. More advanced users may also like to have per-instruction post callback and state comparison callback. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Move verifier's internal structures to a header file and prefix their names with bpf_ to avoid potential namespace conflicts. Those structures will soon be used by external analyzers. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Storing state in reserved fields of instructions makes it impossible to run verifier on programs already marked as read-only. Allocate and use an array of per-instruction state instead. While touching the error path rename and move existing jump target. Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Add cls_bpf support for the TCA_CLS_FLAGS_SKIP_SW flag. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
Add cls_bpf support for the TCA_CLS_FLAGS_SKIP_HW flag. Unlike U32 and flower cls_bpf already has some netlink flags defined. Create a new attribute to be able to use the same flag values as the above. Unlike U32 and flower reject unknown flags. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored
This patch adds hardware offload capability to cls_bpf classifier, similar to what have been done with U32 and flower. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller authored
Jiri Pirko says: ==================== mlxsw: Replace Hw related const with resource query results Nogah says: Many of the ASIC's properties can be read from the HW with resources query. This patchset adds new resources to the resource query and implement using them, instead of the constants that we currently use. Those resources are lag, kvd and router related. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
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Nogah Frankel authored
Replace max rif const with using the result from resource query. Signed-off-by: Nogah Frankel <nogahf@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Nogah Frankel authored
Add the max number of rif (router interfaces) to resource query. Signed-off-by: Nogah Frankel <nogahf@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Nogah Frankel authored
Add max system ports, max regions and max vlan groups to resource query. Signed-off-by: Nogah Frankel <nogahf@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Nogah Frankel authored
Replace max virtual routers const with the result from the resource query. Signed-off-by: Nogah Frankel <nogahf@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Nogah Frankel authored
Add the max number of virtual routers to resource query. Signed-off-by: Nogah Frankel <nogahf@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Nogah Frankel authored
Use resources from resource query to determine values for the profile configuration. Add KVD determined section sizes to the resources struct. Change the profile struct and value to match this changes. Signed-off-by: Nogah Frankel <nogahf@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Nogah Frankel authored
Add KVD size, and minimum sizes for the single and double sections resources to resources query. Signed-off-by: Nogah Frankel <nogahf@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Nogah Frankel authored
Use max lag and max ports in lag resources as the result of resource query instead of using const to save them. Signed-off-by: Nogah Frankel <nogahf@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Nogah Frankel authored
Add max lag and max ports in lag resources to resources query. Signed-off-by: Nogah Frankel <nogahf@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Or Gerlitz authored
The offloads stats functions are local to this file, make them static. Fixes: fc1bbb0f ('mlxsw: spectrum: Implement offload stats ndo [..]') Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller authored
Neal Cardwell says: ==================== tcp: BBR congestion control algorithm This patch series implements a new TCP congestion control algorithm: BBR (Bottleneck Bandwidth and RTT). A paper with a detailed description of BBR will be published in ACM Queue, September-October 2016, as "BBR: Congestion-Based Congestion Control". BBR is widely deployed in production at Google. The patch series starts with a set of supporting infrastructure changes, including a few that extend the congestion control framework. The last patch adds BBR as a TCP congestion control module. Please see individual patches for the details. - v3 -> v4: - Updated tcp_bbr.c in "tcp_bbr: add BBR congestion control" to use const to qualify all the constant parameters. Thanks to Stephen Hemminger. - In "tcp_bbr: add BBR congestion control", remove the bbr_rate_kbps() function, which had a 64-bit divide that would be problematic on some architectures, and just use bbr_rate_bytes_per_sec() directly. Thanks to Kenneth Klette Jonassen for suggesting this. - In "tcp: switch back to proper tcp_skb_cb size check in tcp_init()", switched from sizeof(skb->cb) to FIELD_SIZEOF. Thanks to Lance Richardson for suggesting this. - Updated "tcp_bbr: add BBR congestion control" commit message with performance data, more details about deployment at Google, and another reminder to use fq with BBR. - Updated tcp_bbr.c in "tcp_bbr: add BBR congestion control" to use MODULE_LICENSE("Dual BSD/GPL"). - v2 -> v3: fix another issue caught by build bots: - adjust rate_sample struct initialization syntax to allow gcc-4.4 to compile the "tcp: track data delivery rate for a TCP connection" patch; also adjusted some similar syntax in "tcp_bbr: add BBR congestion control" - v1 -> v2: fix issues caught by build bots: - fix "tcp: export data delivery rate" to use rate64 instead of rate, so there is a 64-bit numerator for the do_div call - fix conflicting definitions for minmax caused by "tcp: use windowed min filter library for TCP min_rtt estimation" with a new commit: tcp: cdg: rename struct minmax in tcp_cdg.c to avoid a naming conflict - fix warning about the use of __packed in "tcp: track data delivery rate for a TCP connection", which involves the addition of a new commit: tcp: switch back to proper tcp_skb_cb size check in tcp_init() ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
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Neal Cardwell authored
This commit implements a new TCP congestion control algorithm: BBR (Bottleneck Bandwidth and RTT). A detailed description of BBR will be published in ACM Queue, Vol. 14 No. 5, September-October 2016, as "BBR: Congestion-Based Congestion Control". BBR has significantly increased throughput and reduced latency for connections on Google's internal backbone networks and google.com and YouTube Web servers. BBR requires only changes on the sender side, not in the network or the receiver side. Thus it can be incrementally deployed on today's Internet, or in datacenters. The Internet has predominantly used loss-based congestion control (largely Reno or CUBIC) since the 1980s, relying on packet loss as the signal to slow down. While this worked well for many years, loss-based congestion control is unfortunately out-dated in today's networks. On today's Internet, loss-based congestion control causes the infamous bufferbloat problem, often causing seconds of needless queuing delay, since it fills the bloated buffers in many last-mile links. On today's high-speed long-haul links using commodity switches with shallow buffers, loss-based congestion control has abysmal throughput because it over-reacts to losses caused by transient traffic bursts. In 1981 Kleinrock and Gale showed that the optimal operating point for a network maximizes delivered bandwidth while minimizing delay and loss, not only for single connections but for the network as a whole. Finding that optimal operating point has been elusive, since any single network measurement is ambiguous: network measurements are the result of both bandwidth and propagation delay, and those two cannot be measured simultaneously. While it is impossible to disambiguate any single bandwidth or RTT measurement, a connection's behavior over time tells a clearer story. BBR uses a measurement strategy designed to resolve this ambiguity. It combines these measurements with a robust servo loop using recent control systems advances to implement a distributed congestion control algorithm that reacts to actual congestion, not packet loss or transient queue delay, and is designed to converge with high probability to a point near the optimal operating point. In a nutshell, BBR creates an explicit model of the network pipe by sequentially probing the bottleneck bandwidth and RTT. On the arrival of each ACK, BBR derives the current delivery rate of the last round trip, and feeds it through a windowed max-filter to estimate the bottleneck bandwidth. Conversely it uses a windowed min-filter to estimate the round trip propagation delay. The max-filtered bandwidth and min-filtered RTT estimates form BBR's model of the network pipe. Using its model, BBR sets control parameters to govern sending behavior. The primary control is the pacing rate: BBR applies a gain multiplier to transmit faster or slower than the observed bottleneck bandwidth. The conventional congestion window (cwnd) is now the secondary control; the cwnd is set to a small multiple of the estimated BDP (bandwidth-delay product) in order to allow full utilization and bandwidth probing while bounding the potential amount of queue at the bottleneck. When a BBR connection starts, it enters STARTUP mode and applies a high gain to perform an exponential search to quickly probe the bottleneck bandwidth (doubling its sending rate each round trip, like slow start). However, instead of continuing until it fills up the buffer (i.e. a loss), or until delay or ACK spacing reaches some threshold (like Hystart), it uses its model of the pipe to estimate when that pipe is full: it estimates the pipe is full when it notices the estimated bandwidth has stopped growing. At that point it exits STARTUP and enters DRAIN mode, where it reduces its pacing rate to drain the queue it estimates it has created. Then BBR enters steady state. In steady state, PROBE_BW mode cycles between first pacing faster to probe for more bandwidth, then pacing slower to drain any queue that created if no more bandwidth was available, and then cruising at the estimated bandwidth to utilize the pipe without creating excess queue. Occasionally, on an as-needed basis, it sends significantly slower to probe for RTT (PROBE_RTT mode). BBR has been fully deployed on Google's wide-area backbone networks and we're experimenting with BBR on Google.com and YouTube on a global scale. Replacing CUBIC with BBR has resulted in significant improvements in network latency and application (RPC, browser, and video) metrics. For more details please refer to our upcoming ACM Queue publication. Example performance results, to illustrate the difference between BBR and CUBIC: Resilience to random loss (e.g. from shallow buffers): Consider a netperf TCP_STREAM test lasting 30 secs on an emulated path with a 10Gbps bottleneck, 100ms RTT, and 1% packet loss rate. CUBIC gets 3.27 Mbps, and BBR gets 9150 Mbps (2798x higher). Low latency with the bloated buffers common in today's last-mile links: Consider a netperf TCP_STREAM test lasting 120 secs on an emulated path with a 10Mbps bottleneck, 40ms RTT, and 1000-packet bottleneck buffer. Both fully utilize the bottleneck bandwidth, but BBR achieves this with a median RTT 25x lower (43 ms instead of 1.09 secs). Our long-term goal is to improve the congestion control algorithms used on the Internet. We are hopeful that BBR can help advance the efforts toward this goal, and motivate the community to do further research. Test results, performance evaluations, feedback, and BBR-related discussions are very welcome in the public e-mail list for BBR: https://groups.google.com/forum/#!forum/bbr-dev NOTE: BBR *must* be used with the fq qdisc ("man tc-fq") with pacing enabled, since pacing is integral to the BBR design and implementation. BBR without pacing would not function properly, and may incur unnecessary high packet loss rates. Signed-off-by: Van Jacobson <vanj@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Nandita Dukkipati <nanditad@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Neal Cardwell authored
The TCP CUBIC module already uses 64 bytes. The upcoming TCP BBR module uses 88 bytes. Signed-off-by: Van Jacobson <vanj@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Nandita Dukkipati <nanditad@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Yuchung Cheng authored
This commit introduces an optional new "omnipotent" hook, cong_control(), for congestion control modules. The cong_control() function is called at the end of processing an ACK (i.e., after updating sequence numbers, the SACK scoreboard, and loss detection). At that moment we have precise delivery rate information the congestion control module can use to control the sending behavior (using cwnd, TSO skb size, and pacing rate) in any CA state. This function can also be used by a congestion control that prefers not to use the default cwnd reduction approach (i.e., the PRR algorithm) during CA_Recovery to control the cwnd and sending rate during loss recovery. We take advantage of the fact that recent changes defer the retransmission or transmission of new data (e.g. by F-RTO) in recovery until the new tcp_cong_control() function is run. With this commit, we only run tcp_update_pacing_rate() if the congestion control is not using this new API. New congestion controls which use the new API do not want the TCP stack to run the default pacing rate calculation and overwrite whatever pacing rate they have chosen at initialization time. Signed-off-by: Van Jacobson <vanj@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Nandita Dukkipati <nanditad@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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Yuchung Cheng authored
Currently the TCP send buffer expands to twice cwnd, in order to allow limited transmits in the CA_Recovery state. This assumes that cwnd does not increase in the CA_Recovery. For some congestion control algorithms, like the upcoming BBR module, if the losses in recovery do not indicate congestion then we may continue to raise cwnd multiplicatively in recovery. In such cases the current multiplier will falsely limit the sending rate, much as if it were limited by the application. This commit adds an optional congestion control callback to use a different multiplier to expand the TCP send buffer. For congestion control modules that do not specificy this callback, TCP continues to use the previous default of 2. Signed-off-by: Van Jacobson <vanj@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Nandita Dukkipati <nanditad@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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