Technical data

System Dump Analyzer
SHOW SPINLOCKS
Table SDA–22 (Cont.) Static Spin Locks
Name Description
MAILBOX Lock for sending messages to mailboxes
POOL Lock on nonpaged pool database
PERFMON Lock for I/O performance monitoring
INVALIDATE Lock for system space translation buffer (TB) invalidation
VIRTCONS Lock for ownership of the virtual console
HWCLK Lock on hardware clock database, including the quadword containing the
due time of the first timer queue entry (EXE$GQ_1ST_TIME) and the
quadword containing the system time (EXE$GQ_SYSTIME)
MEGA Lock for serializing access to fork-wait queue
MCHECK Lock for synchronizing certain machine error handling
EMB Lock for allocating and releasing error logging buffers
Note
The MCHECK and EMB spin locks, formerly separate spin locks in
previous releases of OpenVMS, have been merged. When you analyze
a crash, you might see one or both names when you display static spin
locks.
For each spin lock, fork lock, or device lock in the system, SHOW SPINLOCKS
provides the following information:
• Name of the spin lock (or device name for the device lock)
• Address of the spin lock data structure (SPL)
• The owner CPU’s CPU ID
• IPL at which allocation of the lock is synchronized on a local processor
• Number of nested acquisitions of the spin lock by the processor owning the
spin lock (‘‘Ownership Depth’’)
• Rank of the spin lock
• Number of processors waiting to obtain the spin lock
• Spin lock index (for static spin locks only)
• Timeout interval for spin lock acquisition (in terms of 10 milliseconds)
SHOW SPINLOCKS/BRIEF produces a condensed display of this same
information.
If the system under analysis was executing with full-checking multiprocessing
enabled (according to the setting of the MULTIPROCESSING system parameter),
SHOW SPINLOCKS/FULL adds to the spin lock display the last eight PCs at
which the lock was acquired or released. If applicable, SDA also displays the PC
of the last release of multiple, nested acquisitions of the lock.
SDA–171