HP OpenVMS Systems

AUTOGEN and VIOC cache size (VCC_MAXSIZE)?

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The Question is:

 
Hello,
 
I have tried to increase VCC_MAXSIZE on some systems. Occasionally, if I get
carried away with the size, I get and VASFULL or INSVIRMEM (can't remember
which one) error  displayed on the console when rebooting from doing the
AUTOGEN after putting the new
size in MODPARAMS.DAT. The system then comes up with 0 bytes of VIOC cache
enabled.
 
I know that this error is given when the various different memory allocation
SYSGEN parameters create a virtual address space too large. I have seen some
extracts from Notes conferences indicating that AUTOGEN does not incorporate
the VCC_MAXSIZE figure i
n its calculations and therefore gets 'caught out' trying to adjust for a
correct sizing.
 
To recover from this error I have had to readjust my VCC_MAXSIZE down and
AUTGOEN/REBOOT until I get some VIOC cache.
 
My question is, is there not a formula for calculating the maximum size for
the maximum VCC_MAXSIZE for a given set of other SYSGEN memory tuning
parameters? If so, what is it and why doesn't AUTOGEN know about it and warn
me that I won't get any VIOC cac
he when I reboot?
 
Best Regards
 
Edwin Thornber
 
 

The Answer is :

 
  VCC_MAXSIZE is simply added to the amount of system memory required,
  older versions of AUTOGEN did not account for this.
 
  Each 1GB of process address space set via VIRTUALPAGECNT requires 1MB
  of page table space for the process.  Multiply this by the BALSETCNT
  to determine the number of page tables that must be kept in memory in
  parallel.  The WSMAX setting indicates the number of pages in the
  working set, and each page requires 8 bytes per page for the working
  set list for each process.  Add in the size of the paged and nonpaged
  memory pools, OpenVMS itself, and random other data structures such as
  the VIOC cache.  All of this must fit into S0 and S1 space, which has
  a maximum size of 2GB.
 
  OpenVMS Alpha V7.0 and later improve this -- the page tables move into
  S2 space in V7.0, and the lock manager data structures move from pool
  into S2 space in V7.2, for instance.
 

  

     

     
answer written or last revised on ( 1-FEB-1999 )
     
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