Fine-tune burst settings


Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>ATM drivers
└─>Fine-tune burst settings
In linux kernel since version 2.6.12  
In order to obtain good throughput, the ENI NIC can transfer
multiple words of data per PCI bus access cycle. Such a multi-word
transfer is called a burst.

The default settings for the burst sizes are suitable for most PCI
chipsets. However, in some cases, large bursts may overrun buffers
in the PCI chipset and cause data corruption. In such cases, large
bursts must be disabled and only (slower) small bursts can be used.
The burst sizes can be set independently in the send (TX) and
receive (RX) direction.

Note that enabling many different burst sizes in the same direction
may increase the cost of setting up a transfer such that the
resulting throughput is lower than when using only the largest
available burst size.

Also, sometimes larger bursts lead to lower throughput, e.g. on an
Intel 440FX board, a drop from 135 Mbps to 103 Mbps was observed
when going from 8W to 16W bursts.