Skip to content
  1. May 19, 2020
  3. Mar 23, 2020
  5. Feb 03, 2020
    • Masahiro Yamada's avatar
      kbuild: rename hostprogs-y/always to hostprogs/always-y · 5f2fb52f
      Masahiro Yamada authored 
      

In old days, the "host-progs" syntax was used for specifying host
programs. It was renamed to the current "hostprogs-y" in 2004.

It is typically useful in scripts/Makefile because it allows Kbuild to
selectively compile host programs based on the kernel configuration.

This commit renames like follows:

  always       ->  always-y
  hostprogs-y  ->  hostprogs

So, scripts/Makefile will look like this:

  always-$(CONFIG_BUILD_BIN2C) += ...
  always-$(CONFIG_KALLSYMS)    += ...
      ...
  hostprogs := $(always-y) $(always-m)

I think this makes more sense because a host program is always a host
program, irrespective of the kernel configuration. We want to specify
which ones to compile by CONFIG options, so always-y will be handier.

The "always", "hostprogs-y", "hostprogs-m" will be kept for backward
compatibility for a while.

Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
      5f2fb52f
  7. Jan 21, 2020
  9. Dec 16, 2019
  11. Nov 12, 2019
  13. Nov 11, 2019
  15. Oct 31, 2019
  17. Oct 12, 2019
  19. Oct 08, 2019
  21. Oct 07, 2019
  23. Jul 15, 2019
  25. Jul 03, 2019
    • Stanislav Fomichev's avatar
      samples/bpf: add sample program that periodically dumps TCP stats · 39533884
      Stanislav Fomichev authored 
      

Uses new RTT callback to dump stats every second.

$ mkdir -p /tmp/cgroupv2
$ mount -t cgroup2 none /tmp/cgroupv2
$ mkdir -p /tmp/cgroupv2/foo
$ echo $$ >> /tmp/cgroupv2/foo/cgroup.procs
$ bpftool prog load ./tcp_dumpstats_kern.o /sys/fs/bpf/tcp_prog
$ bpftool cgroup attach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog
$ bpftool prog tracelog
$ # run neper/netperf/etc

Used neper to compare performance with and without this program attached
and didn't see any noticeable performance impact.

Sample output:
  <idle>-0     [015] ..s.  2074.128800: 0: dsack_dups=0 delivered=242526
  <idle>-0     [015] ..s.  2074.128808: 0: delivered_ce=0 icsk_retransmits=0
  <idle>-0     [015] ..s.  2075.130133: 0: dsack_dups=0 delivered=323599
  <idle>-0     [015] ..s.  2075.130138: 0: delivered_ce=0 icsk_retransmits=0
  <idle>-0     [005] .Ns.  2076.131440: 0: dsack_dups=0 delivered=404648
  <idle>-0     [005] .Ns.  2076.131447: 0: delivered_ce=0 icsk_retransmits=0

Cc: Eric Dumazet <edumazet@google.com>
Cc: Priyaranjan Jha <priyarjha@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      39533884
    • brakmo's avatar
      bpf: Add support for fq's EDT to HBM · 71634d7f
      brakmo authored 
      

Adds support for fq's Earliest Departure Time to HBM (Host Bandwidth
Manager). Includes a new BPF program supporting EDT, and also updates
corresponding programs.

It will drop packets with an EDT of more than 500us in the future
unless the packet belongs to a flow with less than 2 packets in flight.
This is done so each flow has at least 2 packets in flight, so they
will not starve, and also to help prevent delayed ACK timeouts.

It will also work with ECN enabled traffic, where the packets will be
CE marked if their EDT is more than 50us in the future.

The table below shows some performance numbers. The flows are back to
back RPCS. One server sending to another, either 2 or 4 flows.
One flow is a 10KB RPC, the rest are 1MB RPCs. When there are more
than one flow of a given RPC size, the numbers represent averages.

The rate limit applies to all flows (they are in the same cgroup).
Tests ending with "-edt" ran with the new BPF program supporting EDT.
Tests ending with "-hbt" ran on top HBT qdisc with the specified rate
(i.e. no HBM). The other tests ran with the HBM BPF program included
in the HBM patch-set.

EDT has limited value when using DCTCP, but it helps in many cases when
using Cubic. It usually achieves larger link utilization and lower
99% latencies for the 1MB RPCs.
HBM ends up queueing a lot of packets with its default parameter values,
reducing the goodput of the 10KB RPCs and increasing their latency. Also,
the RTTs seen by the flows are quite large.

                         Aggr              10K  10K  10K   1MB  1MB  1MB
         Limit           rate drops  RTT  rate  P90  P99  rate  P90  P99
Test      rate  Flows    Mbps   %     us  Mbps   us   us  Mbps   ms   ms
--------  ----  -----    ---- -----  ---  ---- ---- ----  ---- ---- ----
cubic       1G    2       904  0.02  108   257  511  539   647 13.4 24.5
cubic-edt   1G    2       982  0.01  156   239  656  967   743 14.0 17.2
dctcp       1G    2       977  0.00  105   324  408  744   653 14.5 15.9
dctcp-edt   1G    2       981  0.01  142   321  417  811   660 15.7 17.0
cubic-htb   1G    2       919  0.00 1825    40 2822 4140   879  9.7  9.9

cubic     200M    2       155  0.30  220    81  532  655    74  283  450
cubic-edt 200M    2       188  0.02  222    87 1035 1095   101   84   85
dctcp     200M    2       188  0.03  111    77  912  939   111   76  325
dctcp-edt 200M    2       188  0.03  217    74 1416 1738   114   76   79
cubic-htb 200M    2       188  0.00 5015     8 14ms 15ms   180   48   50

cubic       1G    4       952  0.03  110   165  516  546   262   38  154
cubic-edt   1G    4       973  0.01  190   111 1034 1314   287   65   79
dctcp       1G    4       951  0.00  103   180  617  905   257   37   38
dctcp-edt   1G    4       967  0.00  163   151  732 1126   272   43   55
cubic-htb   1G    4       914  0.00 3249    13  7ms  8ms   300   29   34

cubic       5G    4      4236  0.00  134   305  490  624  1310   10   17
cubic-edt   5G    4      4865  0.00  156   306  425  759  1520   10   16
dctcp       5G    4      4936  0.00  128   485  221  409  1484    7    9
dctcp-edt   5G    4      4924  0.00  148   390  392  623  1508   11   26

v1 -> v2: Incorporated Andrii's suggestions
v2 -> v3: Incorporated Yonghong's suggestions
v3 -> v4: Removed credit update that is not needed

Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      71634d7f
  27. Jun 17, 2019
  29. Jun 14, 2019
  31. Jun 11, 2019
  33. Jun 06, 2019
    • Jakub Kicinski's avatar
      samples: bpf: print a warning about headers_install · 07c3bbdb
      Jakub Kicinski authored 
      

It seems like periodically someone posts patches to "fix"
header includes.  The issue is that samples expect the
include path to have the uAPI headers (from usr/) first,
and then tools/ headers, so that locally installed uAPI
headers take precedence.  This means that if users didn't
run headers_install they will see all sort of strange
compilation errors, e.g.:

  HOSTCC  samples/bpf/test_lru_dist
  samples/bpf/test_lru_dist.c:39:8: error: redefinition of ‘struct list_head’
   struct list_head {
          ^~~~~~~~~
   In file included from samples/bpf/test_lru_dist.c:9:0:
   ../tools/include/linux/types.h:69:8: note: originally defined here
    struct list_head {
           ^~~~~~~~~

Try to detect this situation, and print a helpful warning.

v2: just use HOSTCC (Jiong).

Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      07c3bbdb
  35. May 28, 2019
  37. Mar 27, 2019
  39. Mar 02, 2019
    • brakmo's avatar
      bpf: User program for testing HBM · a1270fe9
      brakmo authored 
      The program nrm creates a cgroup and attaches a BPF program to the
cgroup for testing HBM (Host Bandwidth Manager) for egress traffic.
One still needs to create network traffic. This can be done through
netesto, netperf or iperf3.
A follow-up patch contains a script to create traffic.

USAGE: hbm [-d] [-l] [-n <id>] [-r <rate>] [-s] [-t <secs>]
           [-w] [-h] [prog]
  Where:
   -d        Print BPF trace debug buffer
   -l        Also limit flows doing loopback
   -n <#>    To create cgroup "/hbm#" and attach prog. Default is /nrm1
             This is convenient when testing HBM in more than 1 cgroup
   -r <rate> Rate limit in Mbps
   -s        Get HBM stats (marked, dropped, etc.)
   -t <time> Exit after specified seconds (deault is 0)
   -w        Work conserving flag. cgroup can increase its bandwidth
             beyond the rate limit specified while there is available
             bandwidth. Current implementation assumes there is only
             NIC (eth0), but can be extended to support multiple NICs.
             Currrently only supported for egress. Note, this is just
	     a proof of concept.
   -h        Print this info
   prog      BPF program file name. Name defaults to hbm_out_kern.o

More information about HBM can be found in the paper "BPF Host Resource
Management" presented at the 2018 Linux Plumbers Conference, Networking Track
(http://vger.kernel.org/lpc_net2018_talks/LPC%20BPF%20Network%20Resource%20Paper.pdf

)

Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      a1270fe9
    • brakmo's avatar
      bpf: Sample HBM BPF program to limit egress bw · 187d0738
      brakmo authored 
      

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: default avatarLawrence Brakmo <brakmo@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
      187d0738
  41. Feb 28, 2019
  43. Feb 25, 2019