Kernel Tunable Parameters

NSTREVENT

50

Determines the maximum number of outstanding STREAMS bufcalls allowed at any one instance. This needs to be modified if the protocol modules to be incorporated into STREAMS need to have more than 50 bufcalls outstanding at the same time.

STRMSGSZ

8192

Defines the maximum number of bytes that can be sent in the data part of a STREAMS message using the function putmsg and write. putmsg will return ERANGE if a data buffer is sent with a size greater than this value. write will segment the data into multiple messages. If STRMSGSZ is 0, the maximum data message size is infinite.

STRCTLSZ

1024

Defines the maximum number of bytes that can be sent in the control part of a STREAMS message using the function putmsg. putmsg will return ERANGE if a buffer is sent with a size greater than this value. If STRCTLSZ is 0, the maximum control message size is infinite.

NSTRPUSH

16

Defines the maximum number of STREAMS modules that can be pushed onto a single stream.

NSTRSCHED

0

Determines the number of streams scheduler daemons (smpsched) running on a MP system. The default value is 0, which indicates that Streams will determine the number of daemons based on the number of processors in the system. The number of MP streams schedulers created is as follows:

# of processors   # of smpscheds created
---------------   ---------------------
     2-4                   1
     5-8                   2
     8-16                  3
     16+                   4

If a tunable value > 0 is specified, then that value is used to determine the number of MP schedulers (smpsched) created on a MP system. The minimum value for this tunable is 0 and the maximum is 32.

No MP schedulers will be created on a UP system.

Also, regardless of whether a system is MP or UP, there will always be one UP Streams scheduler (supsched).

NOTE: This tunable is for use by specific HP products only. It will likely be removed in future HP-UX releases.

NSTRBLKSCHED

2

Determines the number of blockable Streams scheduler daemons (sblksched) running on a MP system. The default value is 2, which means that two blockable Streams schedulers (sblksched) will be created on a MP system.

If the tunable is set to 0, then no blockable Streams schedulers will be created on a MP system. Also, on a UP system, no blockable Streams schedulers will be created.

streamspipes

0

Determines if pipes are STREAMS-based. If set to zero, pipes are not STREAMS-based. If non-zero, pipes are STREAMS-based. The default is for pipes to not be STREAMS-based.

NOTE: This tunable appears in /usr/conf/master.d/core-hpux.