Patch Name: PHKL_17653

Patch Description: s700 10.20 Perf improvement for TLB purge on 2.0 processors

Creation Date: 99/03/04

Post Date:  99/05/24

Hardware Platforms - OS Releases:
	s700: 10.20

Products: N/A

Filesets:
	OS-Core.CORE-KRN

Automatic Reboot?: Yes

Status: General Superseded

Critical: No

Path Name: /hp-ux_patches/s700/10.X/PHKL_17653

Symptoms:
	PHKL_17653:
	On 2.0 Architecture systems, TLB purge instructions are
	purging more pages than necessary.  This does not cause
	the system to operate improperly, but it may have a
	slight negative impact on system performance.

Defect Description:
	PHKL_17653:
	The problem lies with the PITLB and PDTLB instructions used
	in the 2.0 trap handlers.  The 2.0 architecture was
	enhanced to define that the low-order 4 bits of the
	address that is being purged specifies a "page size"
	(which is defined in Table 3-1 of the PA-RISC 2.0
	Architecture book by Gerry Kane).  However, the 2.0
	trap handlers only need to purge one page, and they do
	not zero the low-order 4 bits of the address that they
	wish to purge (the address that is used is the actual
	address that caused the trap).  This results in many
	more pages being purged than was intended.
	Resolution:
	The code now zero's the low-order 4 bits of the address.

SR:
	4701401646

Patch Files:
	/usr/conf/lib/libhp-ux.a(asm_tlb2_0.o)

what(1) Output:
	/usr/conf/lib/libhp-ux.a(asm_tlb2_0.o):
		asm_tlb2_0.s      $Date: 99/03/04 14:44:16 $ $Revisi
			on: 1.3.98.7 $ PATCH_10.20 (PHKL_17653)

cksum(1) Output:
	841345533 15424 /usr/conf/lib/libhp-ux.a(asm_tlb2_0.o)

Patch Conflicts: None

Patch Dependencies: None

Hardware Dependencies: None

Other Dependencies: None

Supersedes: None

Equivalent Patches:
	PHKL_17258:
	s700: 11.00

Patch Package Size: 70 KBytes

Installation Instructions:
	Please review all instructions and the Hewlett-Packard
	SupportLine User Guide or your Hewlett-Packard support terms
	and conditions for precautions, scope of license,
	restrictions, and, limitation of liability and warranties,
	before installing this patch.
	------------------------------------------------------------
	1. Back up your system before installing a patch.

	2. Login as root.

	3. Copy the patch to the /tmp directory.

	4. Move to the /tmp directory and unshar the patch:

		cd /tmp
		sh PHKL_17653

	5a. For a standalone system, run swinstall to install the
	    patch:

		swinstall -x autoreboot=true -x match_target=true \
			-s /tmp/PHKL_17653.depot

	5b. For a homogeneous NFS Diskless cluster run swcluster on the
	    server to install the patch on the server and the clients:

		swcluster -i -b

	    This will invoke swcluster in the interactive mode and
	    force all clients to be shut down.

	    WARNING: All cluster clients must be shut down prior to the
		     patch installation.  Installing the patch while the
		     clients are booted is unsupported and can lead to
		     serious problems.

	    The swcluster command will invoke an swinstall session in which
	    you must specify:

		alternate root path  -  default is /export/shared_root/OS_700
		source depot path    -  /tmp/PHKL_17653.depot

	    To complete the installation, select the patch by choosing
	    "Actions -> Match What Target Has" and then "Actions -> Install"
	    from the Menubar.

	5c. For a heterogeneous NFS Diskless cluster:

		- run swinstall on the server as in step 5a to install
		  the patch on the cluster server.

		- run swcluster on the server as in step 5b to install
		  the patch on the cluster clients.

	By default swinstall will archive the original software in
	/var/adm/sw/patch/PHKL_17653.  If you do not wish to retain a
	copy of the original software, you can create an empty file
	named /var/adm/sw/patch/PATCH_NOSAVE.

	Warning: If this file exists when a patch is installed, the
	         patch cannot be deinstalled.  Please be careful
		 when using this feature.

	It is recommended that you move the PHKL_17653.text file to
	/var/adm/sw/patch for future reference.

	To put this patch on a magnetic tape and install from the
	tape drive, use the command:

		dd if=/tmp/PHKL_17653.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions: None