AsynchRxPackets registry setting

[BruteForce]

A new registry setting will be available with the forthcoming ubCore
5.13 relase. This registry setting control the buffer size used by the
UBOHCI.SYS driver for receiving asynchronous requests and responses.

Currently the driver allocates space for 64 packets (64 for requests
and 64 for responses).
The new setting called AsynchRxPackets is a REG_DWORD with valid range
from 64 to 256, the default being 64. It is located under HKLM\SYSTEM
\CurrentControlSet\Services\ubohci\Parameters.

Why would someone need to use this setting? Imagine a scenario where
four nodes send heavy asynchronous traffic to a single "controller"
node. A packet from the asynchronous receive request buffer will be
allocated and reserved until the application has retrieved it with
C1394GetNextRequest and somehow serviced it. If the application delays
a bit then it is possible that all receive buffers get exhausted (e.g.
4 nodes with 16 outstanding packets each), in which case the driver
will no longer be able to receive packets until some buffer space is
freed.
In order to lessen the likelihood of this occurring you can use the
AsynchRxPackets setting.

The setting will as usual be configurable through UBTWEAK.

Dimitris Staikos
Unibrain