APAR status
Closed as program error.
Error description
ClearCase MVFS allocates Beta Semaphores inefficiently for mnode allocation on HP-UX 11.31 IA systems ClearCase 7.0.1.3 HP-UX 11.31 IA Problem Explained: Inefficient use of Beta Semaphores, when MVFS allocates mnodes, causes the lock class information hash table to increase in size with each new, unique mnode allocation. As ClearCase is used, say within a build environment, the lock class information hash table increases exponentially: Subsequently, searching the hash table for entries becomes prohibitive, and the system performance begins to suffer. Workaround: NONE
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: * **************************************************************** * PROBLEM DESCRIPTION: * **************************************************************** * RECOMMENDATION: * **************************************************************** The issue is caused due to the way MVFS allocates locks (beta semaphores) to protect its internal data structures. While allocating the locks, MVFS associated every lock with a unique name. This was primarily to aid debugging of locks. On HP-UX 11.31 while initializing the beta semaphore, the kernel creates a data structure of its own using the parameters passed to the initialization routine. One of the parameters that is used is name of the lock. This data structure is maintained as a hash. No other platform (including HP-UX 11.23 or HP-UX 11.11) use the information passed to the initialization routine this way. Entries in the hash are flushed only when system is rebooted. With every lock allocation, the size of the hash increases, hence the time taken to allocate locks increases exponentially.
Problem conclusion
A fix is available in ClearCase versions 7.0.1.10 and 7.1.1.3
Temporary fix
Comments
APAR Information
APAR number
PM14503
Reported component name
CLEARCASE UNIX
Reported component ID
5724G2901
Reported release
701
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-05-13
Closed date
2010-08-19
Last modified date
2010-08-19
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
CLEARCASE UNIX
Fixed component ID
5724G2901
Applicable component levels
R701 PSN
UP
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Document Information
Modified date:
19 August 2010