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authorFan Du <fan.du@intel.com>2015-03-06 11:18:23 +0800
committerDavid S. Miller <davem@davemloft.net>2015-03-06 14:57:41 -0500
commit6b58e0a5f32dedb609438bb9c9c82aa6e23381f2 (patch)
treedcfd707a04fd8295b1384cc18fc60addf22ae23a /include/net/tcp.h
parentdcd8fb8533ceb493146ce030d15f7965b82d0c27 (diff)
downloadlwn-6b58e0a5f32dedb609438bb9c9c82aa6e23381f2.tar.gz
lwn-6b58e0a5f32dedb609438bb9c9c82aa6e23381f2.zip
ipv4: Use binary search to choose tcp PMTU probe_size
Current probe_size is chosen by doubling mss_cache, the probing process will end shortly with a sub-optimal mss size, and the link mtu will not be taken full advantage of, in return, this will make user to tweak tcp_base_mss with care. Use binary search to choose probe_size in a fine granularity manner, an optimal mss will be found to boost performance as its maxmium. In addition, introduce a sysctl_tcp_probe_threshold to control when probing will stop in respect to the width of search range. Test env: Docker instance with vxlan encapuslation(82599EB) iperf -c 10.0.0.24 -t 60 before this patch: 1.26 Gbits/sec After this patch: increase 26% 1.59 Gbits/sec Signed-off-by: Fan Du <fan.du@intel.com> Acked-by: John Heffner <johnwheffner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/tcp.h')
-rw-r--r--include/net/tcp.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 834089b0cffc..1ad82e334e27 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -67,6 +67,9 @@ void tcp_time_wait(struct sock *sk, int state, int timeo);
/* The least MTU to use for probing */
#define TCP_BASE_MSS 1024
+/* Specify interval when tcp mtu probing will stop */
+#define TCP_PROBE_THRESHOLD 8
+
/* After receiving this amount of duplicate ACKs fast retransmit starts. */
#define TCP_FASTRETRANS_THRESH 3