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authorWei Liu <wei.liu2@citrix.com>2015-06-03 10:10:42 (GMT)
committerDavid S. Miller <davem@davemloft.net>2015-06-04 08:09:36 (GMT)
commitc39c4c6abb89d24454b63798ccbae12b538206a5 (patch)
treeb3adde317386125e1b87349821b57f4cb1ebb9aa /net/ipv4/tcp_output.c
parent12e25e1041d044d4204f2b7c54695e14e8ffb282 (diff)
downloadlinux-c39c4c6abb89d24454b63798ccbae12b538206a5.tar.xz
tcp: double default TSQ output bytes limit
Xen virtual network driver has higher latency than a physical NIC. Having only 128K as limit for TSQ introduced 30% regression in guest throughput. This patch raises the limit to 256K. This reduces the regression to 8%. This buys us more time to work out a proper solution in the long run. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_output.c')
-rw-r--r--net/ipv4/tcp_output.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 190538a..eeb59be 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -50,8 +50,8 @@ int sysctl_tcp_retrans_collapse __read_mostly = 1;
*/
int sysctl_tcp_workaround_signed_windows __read_mostly = 0;
-/* Default TSQ limit of two TSO segments */
-int sysctl_tcp_limit_output_bytes __read_mostly = 131072;
+/* Default TSQ limit of four TSO segments */
+int sysctl_tcp_limit_output_bytes __read_mostly = 262144;
/* This limits the percentage of the congestion window which we
* will allow a single TSO frame to consume. Building TSO frames