Tuning the P4 device
Up: Special features of different systems Next: Heterogeneous networks and the ch_p4 device Previous: Using the secure server
The P4 device is normally used for networks of workstations connected using sockets. When a socket connection is established, certain resources are allocated for it; the amount of resources allocated represents a trade-off between performance and memory space. Some systems set their defaults to limit the amount of memory used by the socket connections; this can impact performance. The P4 device allows you to override the defaults by using some environment variables. These are
- P4_SOCKBUFSIZE
-
Size of socket buffers, in bytes. Note that most
systems establish a maximum value for this parameter. Common default values
are 4096 to 16384, and maximum values between 65536 and 262144. Users with
TCP/IP over faster-than-usual networks should experiment with increasing
this value above the default, for example with
setenv P4_SOCKBUFSIZE 52000
- P4_WINSHIFT
- Some socket implementations accept a ``window shift'' parameter that is used to optizmize the process of reassembling the underlying message packets into the original data.
Both of these parameters should be set in your .cshrc file, since they need to be set when all of the processes are created, not just the initial process.
Up: Special features of different systems Next: Heterogeneous networks and the ch_p4 device Previous: Using the secure server
