Any updaate / clarification on this? It looks like this is being reset as mlx4_en tuning parameter.(ofed_scripts/ofa_kernel.spec)
On Mon, Dec 1, 2008 at 9:03 PM, John Russo <[email protected]> wrote: > > Does anyone know why this value is being altered by OFED? > > "net.ipv4.tcp_timestamps" is being set to 0 during OFED installation. > > Default value of this parameter is set to 1 on standard RHEL/SLES distros > which OFED installation script modifies to 0. Also, when OFED is > uninstalled, it does not reset these sysctl parameters to their original > values. > > This parameter is specifically recommended to be turned ON for High > performance network. This is a TCP option that can be used to calculate the > Round Trip Measurement in a better and more accurate way than the > retransmission timeout method can. Accurate value of retransmission timeout > should be determined to avoid unnecessary retransmissions and hence to > improve TCP performance. RFC 1323 talks about this TCP extension for High > Performance. > > When the parameter net.ipv4.tcp_timestamps=1, then it adds extra 12 bytes > into TCP header increasing its size. This has an obvious effect of decrease > in bandwidth as we have some extra data flowing. Is this the reason why OFED > turns it OFF to net.ipv4.tcp_timestamps=0. > _______________________________________________ > general mailing list > [email protected] > http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general > > To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general > _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
