Commit c39c4c6a authored by Wei Liu's avatar Wei Liu Committed by David S. Miller

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: default avatarWei Liu <wei.liu2@citrix.com>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 12e25e10
...@@ -50,8 +50,8 @@ int sysctl_tcp_retrans_collapse __read_mostly = 1; ...@@ -50,8 +50,8 @@ int sysctl_tcp_retrans_collapse __read_mostly = 1;
*/ */
int sysctl_tcp_workaround_signed_windows __read_mostly = 0; int sysctl_tcp_workaround_signed_windows __read_mostly = 0;
/* Default TSQ limit of two TSO segments */ /* Default TSQ limit of four TSO segments */
int sysctl_tcp_limit_output_bytes __read_mostly = 131072; int sysctl_tcp_limit_output_bytes __read_mostly = 262144;
/* This limits the percentage of the congestion window which we /* This limits the percentage of the congestion window which we
* will allow a single TSO frame to consume. Building TSO frames * will allow a single TSO frame to consume. Building TSO frames
......
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