Branch Prediction Patch Management Guideline

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Branch Prediction Patch Management 2.0 05/05/03

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This guideline provides more information about using the branch prediction logic patch

contained in T9070AAJ and T9070AAK and later versions of the T9070 SPRs.

Activating the branch prediction logic patch might impact performance; please read

HOTSTUFF HS02774 (HS02774C as of 2003-APR-23) before you decide to activate the

patch.

NOTE:

If the branch prediction logic patch is already active on the system:

The branch prediction logic patch must be inactive before a new version of the

patch is installed and activated. See instructions under the heading “To disable

patch persistence”.

To activate the patch, you must first install the DIAG2 utility and its OBEY files.

Installing DIAG2 and Its OBEY Files

If you download the SPR files from Scout:

1. Delete local copies of DIAG2.

2. Download all of the SPR files, including the OBEY files INSTBPM,

CHECKALL, APPALL, and DISALL.

3. Copy DIAG2 into $SYSTEM.sysnn.

If you use DSM/SCM to install the SPR:

1. DIAG2 is placed in $SYSTEM.sysnn automatically.

2. Select the branch prediction utility SPR from the product list in DSM/SCM.

3. Double-click the SPR to view its list of files.

4. Select INSTBPM, CHECKALL, APPALL, and DISALL.

5. Click Export on the DSM/SCM screen.

6. When DSM/SCM requests the destination volume, click OK if the default volume

is preferred, or enter a volume name and click OK.

Making Patch Activation Persistent

To activate the branch prediction logic patch persistently across cold loads, you must add

a statement to the current (default) configuration file used by most customers. If you use

multiple configuration files for cold loads (not a common practice), you should make the

change to each configuration file for which you want the patch to apply. The active

configuration file is changed as follows.

Summary of content (5 pages)

PAGE 1
Branch Prediction Patch Management 2.0 05/05/03 Branch Prediction Patch Management Guideline This guideline provides more information about using the branch prediction logic patch contained in T9070AAJ and T9070AAK and later versions of the T9070 SPRs. Activating the branch prediction logic patch might impact performance; please read HOTSTUFF HS02774 (HS02774C as of 2003-APR-23) before you decide to activate the patch.
PAGE 2
Branch Prediction Patch Management 2.0 05/05/03 To make the branch prediction patch active in all processors, use the super ID (255,255) to run the SCF OBEY command file INSTBPM. INSTBPM configures and runs the patch utility DIAG2. This process, with the symbolic name $ZBR, uses the terminal interface defined for $ZHOME. $ZBR is added to the current kernel subsystem configuration for the persistence monitor, $ZZKRN.
PAGE 3
Branch Prediction Patch Management 2.0 05/05/03 To disable patch persistence: When you no longer want the patch to be active after a processor reload or cold start, you must remove $ZBR from the kernel subsystem configuration so that DIAG2 does not run again. 1. $ZBR must be in a stopped state to be removed. To stop $ZBR, at the TACL prompt, enter this command as the super ID: SCF ABORT PROCESS $ZZKRN.#ZBR Note: The ABORT command does not make the patch inactive. 2.
PAGE 4
Branch Prediction Patch Management 2.0 05/05/03 Running DIAG2 Interactively To run the DIAG2 program in interactive mode, at the TACL prompt, enter this command as the super ID: DIAG2 / CPU number / CPU number is the number of the processor to which the command applies. The processor in which DIAG2 runs is the processor affected by the command.
PAGE 5
Branch Prediction Patch Management 2.0 05/05/03 param is one of these options: NOPROMPT Display the current state of the patch (active, not active, or not needed by the processor). APPLYPATCH Make the patch active and display the state of the patch to verify that the patch is active. DISABLEPATCH Make the patch inactive and display the state of the patch to verify that the patch is inactive.