STREAMS-UX Programmer's Guide (February 2007)

STREAMS Kernel Tunable Parameters
STRMSGSZ
Appendix H
306
STRMSGSZ
The maximum size of streams message data (bytes).
Values
Failsafe
0
Default
0
Allowed
0 - 2147483647
Recommended
0
Description
This tunable limits the number of bytes of message data that can be inserted by putmsg() or write() in the
data portion of any streams message on the system. If the tunable is set to zero, there is no limit on how many
bytes can be placed in the data segment of the message.
putmsg() returns ERANGE if the buffer being sent is larger than the current value of STRCTLSZ. write()
segments the data into multiple messages.
Who is Expected to Change This Tunable?
Any customer.
Restrictions on Changing
Changes to this tunable take effect at the next reboot.
When Should the Value of This Tunable Be Raised?
The tunable should be increased if the STREAMS modules or drivers require more bytes than the current
value in the data portion of any streams message.
What are the Side Effects of Raising the Value of This Tunable?
The kernel will use more memory. During low memory situations, it may bring reduce system performance
due to frequent swapping.