The parameters related to spinlock pools for multiprocessor
computers are used similarly and are documented together here. Each
parameter allocates the specified number of spinlocks for the corresponding
system resource:
These parameters are for use by advanced users only who have
a thorough understanding of how spinlocks are used by multiple processors
and how the number of spinlocks needed are related to system size
and complexity. Do not change these from their default value unless
you understand the consequences of any changes. In general, these
values should not be altered without the advice of HP support engineers
who are thoroughly familiar with their use.
Setting these parameters to inappropriate values can result
in severe performance problems in multiprocessor systems.
Acceptable
Values |
 |
All of these parameters have the same minimum and maximum
values. Only the defaults are different as indicated:
- Minimum
64
- Maximum
4096
- Default
64 (ftable_hash_locks, io_ports_hash_locks)
- Default
128 (bufcache_hash_locks, pfdat_hash_locks, region_hash_locks, sysv_hash_locks, vnode_hash_locks, vnode_cd_hash_locks)
- Default
256 (chanq_hash_locks)
Specify a value that is an integer exponent of 2. If you specify
any other value, SAM or the kernel itself will change the parameter
value to the next larger integer exponent of two (for example, specifying
100 results in the value of 128. For more information, see “How to Specify Configurable
Parameter Values”.
Description |
|
In simple terms, spinlocks are a mechanism used in multiple-processor
systems to control the interaction of processors that must be held
off while waiting for another processor to finish a task so the
results can be passed to the waiting processor. Spinlocks control
access to file system vnodes, I/O ports, buffer cache, and various
other resources.
Earlier HP-UX versions allocated a fixed number of spinlocks
for all resources, but beginning with HP-UX 11.0, spinlocks can
be allocated for each resource type to accommodate very large and
complex systems.
In general, if the system is encountering lock contention
problems that are associated with one of these hashed pools, first
identify the resource spinlock pool that is associated with the
contention, then increase the spinlock pool parameter for that resource.
As stated above, these parameters are for use by experienced,
knowledgeable system administrators only. They should not be altered
unless you are quite certain that what you are doing is the correct
thing to do.
Printable version
