Patch Name:  PHKL_2755

Patch Description: s700 9.0[357] fix dynamic buffer cache performance problem

In 9.03 MR, the dynamic buffer cache was allowed to take all of RAM; this
patch limits the buffer cache to physmem/2 as a maximum size and will not
grow the buffer cache if "dbc_cushion" (new variable added with this patch)
pages of memory are not free.

The problem is that we never really want the buffer cache
taking all of RAM; it does indeed try to do this in stock 9.03;
so we are patching things up in the following way: dbc_ceiling
will be set to physmem/2 (instead of physmem), and a new variable
"dbc_cushion" will be introduced that will be the amount of
free 4k pages that must exist for the dynamic buffer cache to be
allowed to grow. We'll default this to 512 (2 MB) but of course,
the customer can change it via adb.

(This is the 9.03 700 version of the patch PHKL_2333 - series 300)

Path Name:  /hp-ux_patches/s700/9.X/PHKL_2755

Effective Date:  931111

Repost: 94/05/24
        The patch was modified to allow installation on HP-UX 9.05.

Repost: 95/07/20
        The patch was modified to allow installation on HP-UX 9.07.

OS Release:  9.03 9.05 9.07

Reboot Required:  Yes

Patch Files:  
/system/PHKL_2755/new/dbc_bio.o
/system/PHKL_2755/new/ufs_mchdep.o

SR#:  None

"what" string/timestamp:  
dbc_bio.o:
         dbc_bio.c    $Revision: 1.2.61.17 $ $Date: 93/11/11 10:48:59 $
PATCH_9.03 (PHKL_2755)
ufs_mchdep.o:
         ufs_mchdep.c $Revision: 1.11.61.14 $ $Date: 93/11/11 10:47:54 $
PATCH_9.03 (PHKL_2755)


"sum" output:  
42180 13 dbc_bio.o
44494 17 ufs_mchdep.o


Dependencies:  None

Supersedes:  None

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.

     Note: Please back up your system before you patch.

---------------------------------------------------------------------------
After getting the patch onto your machine, unshar the patch (sh PHKL_2755).

To install this patch do the following:
1) Run /etc/update (Note: you must be logged in as root to update
   a system).
2) Once in the update "Main Menu" move the highlighted line to "Change
   Source or Destination ->" and press "Return" or "Select Item".
3) Make sure the highlighted item in the "Change Source or Destination"
   window is "From Tape Device to Local System ...", then press "Return" or
   "Select Item".
4) You should now be in the "From Tape Device to Local System" window.
   Change the "Source:  /dev/rmt/0m" to "Source: /tmp/PHKL_2755.updt"
   (this assumes that you are in the /tmp directory where PHKL_2755.updt
   has been placed).  Note: You must enter the complete path name.
5) Press "Done".
6) From here on follow the standard directions for update.

The customized script that update runs will move the original software
to /system/PHKL_2755/orig.  HP recommends keeping this software there in
order to recover from any potential problems.  It is also recommended that
you move the PHKL_2755.text file to /system/PHKL_2755 to be retained for
future reference.

If you wish to put this patch on a magnetic tape and update from the tape
drive, dd a copy of the patch to the tape drive.  As an example the
following will create a copy of the patch that update can read:
dd if=PHKL_2755.updt of=/dev/rmt/0m bs=2048