Patch Name: PHKL_30089

Patch Description: s700_800 11.23 clock int skew to improve performance

Creation Date: 03/11/25

Post Date: 04/01/06

Hardware Platforms - OS Releases:
	s700: 11.23
	s800: 11.23

Products: N/A

Filesets:
	OS-Core.CORE2-KRN,fr=B.11.23,fa=HP-UX_B.11.23_IA,v=HP

Automatic Reboot?: Yes

Status: General Release

Critical: No

Category Tags:
	defect_repair general_release

Path Name: /hp-ux_patches/s700_800/11.X/PHKL_30089

Symptoms:
	PHKL_30089:
	( SR:8606326711 CR:JAGae88987 )
	Customers with larger configurations that are running
	performance sensitive applications will not be getting
	the full performance from those applications because
	of this problem.  Specifically it was found that a 6%
	improvement in Linpack results were achieved after the
	fix was applied.

Defect Description:
	PHKL_30089:
	( SR:8606326711 CR:JAGae88987 )
	All of the CPUs get their clock interrupt at exactly the
	same instant in time which causes unnecessary lock
	contention.  The lock contention has been observed to
	reduce performance on certain application benchmarks.

	Resolution:
	To resolve lock contentions problems, clock interrupts on
	each CPU are skewed so as to occur at different times.
	The skew value is measured in cpu cycles and is relatively
	small, however it is large enough to reduce the lock
	contention significantly.

Enhancement:
	No

SR:
	8606326711

Patch Files:
	
	OS-Core.CORE2-KRN,fr=B.11.23,fa=HP-UX_B.11.23_IA,v=HP:
	/usr/conf/lib/libclock-pdk.a(clock.o)

what(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.23,fa=HP-UX_B.11.23_IA,v=HP:
	/usr/conf/lib/libclock-pdk.a(clock.o):
		clock.c $Date: 2003/11/20 16:38:01 $Revision: r11.23
			/1 PATCH_11.23 (PHKL_30089)

cksum(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.23,fa=HP-UX_B.11.23_IA,v=HP:
	3683271257 103744 /usr/conf/lib/libclock-pdk.a(clock.o)

Patch Conflicts: None

Patch Dependencies: None

Hardware Dependencies: None

Other Dependencies: None

Supersedes: None

Equivalent Patches: None

Patch Package Size: 50 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_30089

	5. Run swinstall to install the patch:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -s /tmp/PHKL_30089.depot

	By default swinstall will archive the original software in 
	/var/adm/sw/save/PHKL_30089.  If you do not wish to retain a
	copy of the original software, include the patch_save_files
	option in the swinstall command above:

		-x patch_save_files=false

	WARNING: If patch_save_files is false when a patch is installed,
		 the patch cannot be deinstalled.  Please be careful
		 when using this feature.

	For future reference, the contents of the PHKL_30089.text file is 
	available in the product readme:

		swlist -l product -a readme -d @ /tmp/PHKL_30089.depot

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

		dd if=/tmp/PHKL_30089.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions: None