Chapter 4
Performance Tuning
This chapter discusses performance tuning topics for IRIX and SGI ProPack for Linux.
For good TCP performance, the socket buffers used by applications must be at least
as large as the bandwidth-round trip delay product between the two endpoints.
Normally, larger socket buffers are called for with 10–Gbit Ethernet than when
lower-bandwidth network interface cards are used.

IRIX Performance Tuning

This section discusses the following:
• "Jumbo Frames and IRIX" on page 17
• "Read/Write Size and IRIX" on page 18
• "Socket Buffer Size and IRIX" on page 18
• "Multibuffer Mode and IRIX" on page 18
There is no one tuning configuration that is best for all environments. This section
gives guidelines for the following cases:
•Apoint-to-point configuration, in which IRIX is transmitting to or receiving from
IRIX
•Amulticlient configuration, in which an IRIX system is connected via 10-Gbit
Ethernet to a switch that fans out to multiple clients via 1-Gbit Ethernet

Jumbo Frames and IRIX

In general, an MTU of 9000 bytes (known as jumbo frames) gives the best TCP
throughput performance and scaling results. Avoid an MTU of 1500 bytes if possible.
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