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| author | Eric Dumazet <edumazet@google.com> | 2018-11-11 16:34:28 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-11-11 22:57:03 +0100 |
| commit | c73e5807e4f6fc6d373a5db55b45f639f8bb6328 (patch) | |
| tree | 09c332f796e245e7ec15cc31905e61f793da451b /Documentation/networking/ip-sysctl.txt | |
| parent | Merge branch 'tcp-tso-defer-improvements' (diff) | |
| download | linux-c73e5807e4f6fc6d373a5db55b45f639f8bb6328.tar.xz linux-c73e5807e4f6fc6d373a5db55b45f639f8bb6328.zip | |
tcp: tsq: no longer use limit_output_bytes for paced flows
FQ pacing guarantees that paced packets queued by one flow do not
add head-of-line blocking for other flows.
After TCP GSO conversion, increasing limit_output_bytes to 1 MB is safe,
since this maps to 16 skbs at most in qdisc or device queues.
(or slightly more if some drivers lower {gso_max_segs|size})
We still can queue at most 1 ms worth of traffic (this can be scaled
by wifi drivers if they need to)
Tested:
# ethtool -c eth0 | egrep "tx-usecs:|tx-frames:" # 40 Gbit mlx4 NIC
tx-usecs: 16
tx-frames: 16
# tc qdisc replace dev eth0 root fq
# for f in {1..10};do netperf -P0 -H lpaa24,6 -o THROUGHPUT;done
Before patch:
27711
26118
27107
27377
27712
27388
27340
27117
27278
27509
After patch:
37434
36949
36658
36998
37711
37291
37605
36659
36544
37349
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking/ip-sysctl.txt')
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index aa9e6a331679..af2a69439b93 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -759,7 +759,7 @@ tcp_limit_output_bytes - INTEGER flows, for typical pfifo_fast qdiscs. tcp_limit_output_bytes limits the number of bytes on qdisc or device to reduce artificial RTT/cwnd and reduce bufferbloat. - Default: 262144 + Default: 1048576 (16 * 65536) tcp_challenge_ack_limit - INTEGER Limits number of Challenge ACK sent per second, as recommended |