Appendix B. Performance Tools and Optimization
NetXen, Inc.
Intelligent NIC Getting Started Guide — NDA Required
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net.ipv4.tcp_rmem
- memory reserved for TCP receive buffers (reserved memory per
connection default).
net.core.rmem_default
- TCP receive window default size
net.core.rmem_max
- maximum TCP receive window size
The tunable parameters for the TCP transmit buffers are:
net.ipv4.tcp_wmem
- memory reserved for TCP send buffers (reserved memory per
connection default).
net.core.wmem_default
- TCP send window default size
net.core.wmem_max
- maximum TCP send window size
Other Linux tunable parameters are:
net.ipv4.tcp_mem
- default memory reserved.
net.core.optmem_max
- increase optional max memory to a higher value
net.core.netdev_max_backlog
- increase number of incoming connections backlog
net.core.somaxconn
- increase number of incoming connections backlog
The optimal values for these tunable parameters are typically workload-specific (and
sometimes system-specific). A thorough familiarity with the affects of these parameter
values, as well as an understanding of the target workload and system configuration
(amount of memory, etc), will help in determining the optimal values for these parameters.
