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| author |   Yousuk Seung <ysseung@google.com> | 2018-06-27 10:32:19 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2018-06-28 22:06:24 +0900 |
| commit | 0a9fe5c375b57fab6d18ed0a6a7f935eefb09db3 (patch) | |
| tree | 2ebbbe9b1eb758fb6df0d2ceef78bcb4e9924875 /include/uapi | |
| parent | netlink: Return extack message if attribute validation fails (diff) | |
| download | linux-dev-0a9fe5c375b57fab6d18ed0a6a7f935eefb09db3.tar.xz linux-dev-0a9fe5c375b57fab6d18ed0a6a7f935eefb09db3.zip | |
netem: slotting with non-uniform distribution
Extend slotting with support for non-uniform distributions. This is
similar to netem's non-uniform distribution delay feature.
Commit f043efeae2f1 ("netem: support delivering packets in delayed
time slots") added the slotting feature to approximate the behaviors
of media with packet aggregation but only supported a uniform
distribution for delays between transmission attempts. Tests with TCP
BBR with emulated wifi links with non-uniform distributions produced
more useful results.
Syntax:
slot dist DISTRIBUTION DELAY JITTER [packets MAX_PACKETS] \
[bytes MAX_BYTES]
The syntax and use of the distribution table is the same as in the
non-uniform distribution delay feature. A file DISTRIBUTION must be
present in TC_LIB_DIR (e.g. /usr/lib/tc) containing numbers scaled by
NETEM_DIST_SCALE. A random value x is selected from the table and it
takes DELAY + ( x * JITTER ) as delay. Correlation between values is not
supported.
Examples:
Normal distribution delay with mean = 800us and stdev = 100us.
> tc qdisc add dev eth0 root netem slot dist normal 800us 100us
Optionally set the max slot size in bytes and/or packets.
> tc qdisc add dev eth0 root netem slot dist normal 800us 100us \
bytes 64k packets 42
Signed-off-by: Yousuk Seung <ysseung@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/pkt_sched.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h index 37b5096ae97b..bad3c03bcf43 100644 --- a/include/uapi/linux/pkt_sched.h +++ b/include/uapi/linux/pkt_sched.h @@ -539,6 +539,7 @@ enum { TCA_NETEM_LATENCY64, TCA_NETEM_JITTER64, TCA_NETEM_SLOT, + TCA_NETEM_SLOT_DIST, __TCA_NETEM_MAX, }; @@ -581,6 +582,8 @@ struct tc_netem_slot { __s64 max_delay; __s32 max_packets; __s32 max_bytes; + __s64 dist_delay; /* nsec */ + __s64 dist_jitter; /* nsec */ }; enum { |