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Eric Dumazet authored
When adding rb-tree for TCP retransmit queue, we inadvertently broke TCP autocorking. tcp_should_autocork() should really check if the rtx queue is not empty. Tested: Before the fix : $ nstat -n;./netperf -H 10.246.7.152 -Cc -- -m 500;nstat | grep AutoCork MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.246.7.152 () port 0 AF_INET Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 540000 262144 500 10.00 2682.85 2.47 1.59 3.618 2.329 TcpExtTCPAutoCorking 33 0.0 // Same test, but forcing TCP_NODELAY $ nstat -n;./netperf -H 10.246.7.152 -Cc -- -D -m 500;nstat | grep AutoCork MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.246.7.152 () port 0 AF_INET : nodelay Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 540000 262144 500 10.00 1408.75 2.44 2.96 6.802 8.259 TcpExtTCPAutoCorking 1 0.0 After the fix : $ nstat -n;./netperf -H 10.246.7.152 -Cc -- -m 500;nstat | grep AutoCork MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.246.7.152 () port 0 AF_INET Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 540000 262144 500 10.00 5472.46 2.45 1.43 1.761 1.027 TcpExtTCPAutoCorking 361293 0.0 // With TCP_NODELAY option $ nstat -n;./netperf -H 10.246.7.152 -Cc -- -D -m 500;nstat | grep AutoCork MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.246.7.152 () port 0 AF_INET : nodelay Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 540000 262144 500 10.00 5454.96 2.46 1.63 1.775 1.174 TcpExtTCPAutoCorking 315448 0.0 Fixes: 75c119af ("tcp: implement rb-tree based retransmit queue") Signed-off-by:
Eric Dumazet <edumazet@google.com> Reported-by:
Michael Wenig <mwenig@vmware.com> Tested-by:
Michael Wenig <mwenig@vmware.com> Signed-off-by:
Eric Dumazet <edumazet@google.com> Reported-by:
Michael Wenig <mwenig@vmware.com> Tested-by:
Michael Wenig <mwenig@vmware.com> Acked-by:
Neal Cardwell <ncardwell@google.com> Acked-by:
Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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