Message ID | 1433326242-4061-1-git-send-email-wei.liu2@citrix.com |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
On Wed, 2015-06-03 at 11:10 +0100, Wei Liu wrote: > 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> > --- > net/ipv4/tcp_output.c | 4 ++-- > 1 file 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 Acked-by: Eric Dumazet <edumazet@google.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Wei Liu <wei.liu2@citrix.com> Date: Wed, 3 Jun 2015 11:10:42 +0100 > 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> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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
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> --- net/ipv4/tcp_output.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)