Optimizing Large Vxibus Transfers - National Instruments VXI-1394 User Manual

Note MAX includes configuration options that affect low-level functions and shared
memory, as well as trigger mappings and other attributes of your VXI system. Refer to the
MAX online help for information regarding these options.

Optimizing Large VXIbus Transfers

© National Instruments Corporation
Table 3-1 summarizes the topics the example programs address. All files
are in the
VXIpnp\WinNT\NIvisa\Examples
subdirectories listed below.
Table 3-1. NI-VISA/NI-VXI Examples
Coverage
Message-Based
Access
High-Level
Register Access
Low-Level
Register Access
Sharing Memory
Interrupt Handling
Trigger Handling
For best performance, keep the following in mind when using
or :
VXImove()
• Make sure your buffers are 32-bit aligned.
• Transfer 32-bit data whenever possible.
• Use VXI block access privileges to significantly improve performance
to devices that are capable of accepting block transfers.
• To optimize move performance on virtual memory systems, lock the
user buffer in memory yourself so the move operation does not need to
lock the buffer.
• To optimize move performance on paged memory systems, use
a contiguous buffer so the move operation does not need to build
a scatter-gather list for the user buffer.
Chapter 3
NI-VISA Example
General\RdWrt.c
VXI-VME\HighReg.c
VXI-VME\LowReg.c
VXI-VME\ShareSys.c
VXI-VME\AsyncIntr.c
and
WaitIntr.c
VXI-VME\WaitTrig.c
3-7
Developing Your Application
directory, in the
NI-VXI Example
(Optional)
VXIws.c
VXIhigh.c
VXIlow.c
VXImem.c
VXIint.c
VXItrig.c
viMove()
VXI-1394 User Manual for Windows