Patch Name:  PHKL_11316

Patch Description: s700 10.20 Performance improvement for UFS inode locking

Creation Date: 97/06/16

Post Date:  97/06/17

Hardware Platforms - OS Releases:
        s700: 10.20

Products: N/A

Filesets:
        OS-Core.CORE-KRN

Automatic Reboot?: Yes

Status: General Superseded

Critical:
        Yes
        PHKL_11316: HANG
                The system hangs when a large number of users try
                to log in/out of the system simultaneously.

Path Name:  /hp-ux_patches/s700/10.X/PHKL_11316

Symptoms:
        PHKL_11316:
        A system "HANG" occurs whenever a large number of users
        log In/Out at the same time. The password file has large
        number of entries and the system can have around 1000
        concurrent connections. Problem occurs when many
        processes try to access the same file concurrently, the
        inode locking routines start dealing with the contention
        very inefficiently.

Defect Description:
        PHKL_11316:
        Classic "thundering herd" problem was made worse by the
        fact that the first thing each woken process did was to
        try to lock a "COMMON" spinlock. A process that gets
        the spinlock first, locks the INODE and releases the
        spinlock has to try hard to be able to get the spinlock
        second time while it tries to unlock the same inode.
        Hence the inode was locked whilst no useful work was
        being done.

SR:
        4701349175

Patch Files:
        /usr/conf/lib/libufs.a(ufs_inode.o)

what(1) Output:
        /usr/conf/lib/libufs.a(ufs_inode.o):
                ufs_inode.c $Date: 97/06/07 17:16:55 $ $Revision: 1.
                        48.98.10 $ PATCH_10.20 (PHKL_11316)

cksum(1) Output:
        3465523189 26652 /usr/conf/lib/libufs.a(ufs_inode.o)

Patch Conflicts: None

Patch Dependencies:  None

Hardware Dependencies:  None

Other Dependencies:  None

Supersedes:  None

Equivalent Patches:
        PHKL_11317:
        s800: 10.20

        PHKL_10487:
        s800: 10.01

        PHKL_10486:
        s700: 10.01

Patch Package Size:  80 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_11316

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

                swinstall -x autoreboot=true -x match_target=true \
                        -s /tmp/PHKL_11316.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_11316.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_11316.  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_11316.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_11316.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions:  None