User manual

VSMP Reference

IDLE sets whether VCPU threads should hibernate at host OS level when VMS is executing idle loop.

IDLE=ON enables hibernation. IDLE=OFF disables hibernation and causes threads to spin in OpenVMS

idle loop without attempting to hibernate. IDLE=NEVER disables hibernation and instructs VSMP even

not to hook into OpenVMS idle loop. If IDLE setting is specified as ON or OFF for VSMP LOAD command,

its value can be later dynamically changed with VSMP SET command. If it is specified as NEVER, its value

cannot be subsequently changed until the system is rebooted.

If ILK synchronization window is used (SYNCW=ILK or SYNW=ALL), IDLE cannot be specified as NEVER,

and value of NEVER in this case will be overriden to OFF.

TIMESYNC setting enables or disables operation of TIMESYNC feature. TIMESYNC=ON enables it,

TIMESYNC=OFF disables it. The value of this setting can subsequently be changed dynamically with

VSMP SET command.

INTERLOCK setting selects whether VAX MP will be using portable implementation of VAX interlocked

instructions based on thread-level locking or native implementation, utilizing host-specific interlocked

instructions and not using locking thread-level wherever possible and is thus potentially more

performant and scalable. Portable mode is selected with INTERLOCK=PORTABLE. Native mode is

selected with INTERLOCK=NATIVE. See section “Interprocessor synchronization window” for more

detailed description of this feature. Use of native interlock mode requires also the use of

synchronization window, with SYNCW=ILK or SYNCW=(SYS,ILK). Default it INTERLOCK=PORTABLE.

SYNCW setting selects synchronization windows to be used. See section “Interprocessor synchronization

window” for more detailed description of this feature. Default is SYNCW=NONE. SYNCW=ILK selects ILK

window. SYNCW=SYS selects SYS window. SYNCW=(SYS,ILK) or SYNCW=ALL select both windows.

SYNCW_SYS and SYNCW_ILK define a percentage of SYS and ILK windows size that can be allocated by

VAX MP to permitted interprocessor drift. These parameters are intended for use by VAX MP developers

only and their use requires thorough understanding of VAX MP interprocessor synchronization window

logics. Default value for both is 66, valid range is 10 to 90.

XQTIMEOUT changes DEQNA and DELQA transmit timeout from default of 5 seconds to a specified

higher value. Default is 255 seconds (XQTIMEOUT=255), allowed range is 5 to 255 seconds. If XQ

transmit timeout is set or left too short, involuntary VAX MP thread preemption by host OS may cause

this timeout to expire and OpenVMS falsely decide that XQ controller failed and shut the controller

down. It is recommended to use XQTIMEOUT default of 255 seconds.

NOPATCH=(list) instructs VSMP LOAD not to install specified patches to OpenVMS kernel and/or drivers.

List argument is the list of VSMP patch IDs not to install, for example: NOPATCH=RESCHED or

NOPATCH=(XDELTA, CHSEP). Disabling patches is strongly discouraged – patches are there for a reason

and disabling patches may result in unreliable system prone to crashes and/or data corruption or under-

performant system. For a list of VSMP patch IDs see the table below.