On Fri, 16 Jun 2006 09:01:23 -0700 Harry Edmon <[EMAIL PROTECTED]> wrote:
> I have a system with a strange network performance degradation from > 2.6.11.12 to most recent kernels including 2.6.16.20 and 2.6.17-rc6. > The system is has Dual single core Xeons with hyperthreading on. The > application is the LDM system from UCAR/Unidata > (http://www.unidata.ucar.edu/software/ldm). This system requests > weather data from a variety of systems using RPC calls over a reserved > TCP port (388), puts them into a memory mapped queue file, and then > sends the data out to a variety of downstream requesting systems, again > using RPC calls. When the load is heavy, the 2.6.16.20 kernel falls way > behind with the data ingestion. The 2.6.11.12 kernel does not. I have > tried an experiment with a 2.6.17-rc6 system where it just does the > ingestion, and not the downstream distribution, and it is able to keep > up. I would really appreciate any pointers as to where the problem may > be and how to diagnose it. I have attached the config files from both > kernels and the sysctl.conf file I am using. I have also included the > output from "netstat -s" on the 2.6.16.20 system during a time when it > was having problems. > (added netdev) A quick grep indicates that it isn't using TCP_NODELAY - we've had problems with that in the past. Perhaps a tcpdump of the net traffic will help to determine what's going on. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
