Tuning BAP System Parameters

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HP OpenVMS System Manager's Manual, Volume 2:...

Managing System Parameters

Modifying System Parameters with a Conversational Boot

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Tuning BAP System Parameters

OpenVMS Alpha Version 7.1 and later contains system parameters that control the operation of bus-addressable pool (BAP).

The CIPCA, CIXCD, KFMSB, and Qlogic 1020ISP adapters are some of the adapters that use bus-addressable pool to improve performance. BAP is a non-paged dynamic, physical-address-filtered memory pool used to overcome I/O bus and 32-bit adapter physical addressing limits.

The following table lists the system parameters that control BAP operation along with their default values:

System Parameter Default Value

NPAG_BAP_MIN
0

NPAG_BAP_MAX
0

NPAG_BAP_MIN_PA
0

NPAG_BAP_MAX_PA
-1

System Parameter	Default Value
NPAG_BAP_MIN	0
NPAG_BAP_MAX	0
NPAG_BAP_MIN_PA	0
NPAG_BAP_MAX_PA	-1

The default values of these parameters allow the system to boot with any configuration. When AUTOGEN is run on a configured system, it resets these parameters to values that should enhance performance for the current system configuration.

If the system fails to boot after an installation, upgrade, or configuration change, and displays a message that refers to incorrect BAP parameters, HP recommends that you perform the following steps:

Reset the BAP parameters to the default values.

Reboot the system.

Allow the installation procedure to run AUTOGEN, or manually run AUTOGEN yourself.

A typical AUTOGEN with FEEDBACK command to set these parameters follows:

$ @SYS$UPDATE:AUTOGEN SAVPARAMS SETPARAMS FEEDBACK

These parameters are critical. HP recommends that you run AUTOGEN as described to ensure that they are set correctly.

If you prefer not to use this command because you want to adjust only the BAP parameters settings, use the following procedure:

Boot the system using the default BAP parameter values.

Manually run SYS$SYSTEM:AGEN$FEEDBACK.EXE:
```
$ RUN SYS$SYSTEM:AGEN$FEEDBACK.EXE
```

Search SYS$SYSTEM:AGEN$FEEDBACK.DAT for the BAP_* system parameter values:
```
$ SEARCH SYS$SYSTEM:AGEN$FEEDBACK.DAT "BAP_"
```

Run SYSGEN to set the following system parameters with the BAP values you obtained in Step 3:

AGEN$FEEDBACK Data System Parameter Units

BAP_MIN
NPAG_BAP_MIN
bytes

BAP_MAX
NPAG_BAP_MAX
bytes

BAP_MIN_PA
NPAG_BAP_MIN_PA
Mbytes¹

BAP_MAX_PA
NPAG_BAP_MAX_PA
Mbytes

AGEN$FEEDBACK Data	System Parameter	Units
BAP_MIN	NPAG_BAP_MIN	bytes
BAP_MAX	NPAG_BAP_MAX	bytes
BAP_MIN_PA	NPAG_BAP_MIN_PA	Mbytes¹
BAP_MAX_PA	NPAG_BAP_MAX_PA	Mbytes

The BAP allocation amount (specified by BAP_MIN and BAP_MAX) depends on the adapter type, the number of adapters, and the version of the operating system. The physical address range (specified by BAP_MIN_PA and BAP_MAX_PA) depends on the adapter type and the way the Galaxy logical partitions, if any, are defined.

If you manually set parameters NPAG_BAP_MIN_PA and NPAG_BAP_MAX_PA, be sure to specify the value for each parameter in the correct units (bytes or megabytes) for your operating system version.

Footnotes

1 On OpenVMS Alpha systems prior to Version 7.2, the value of this parameter is specified in bytes.

( Number takes you back )

Modifying System Parameters with a Conversational Boot

Managing Page, Swap, and Dump Files