Performance Tuning

What is the use of profile paramater ztta/roll_area?

echtscorp Memory Management, Performance Tuning

The roll area is one of several memory areas, which satisfies the user requests of user programs. For technical reasons, however, the first 250 KB or so of a user context are always stored in the roll area, further data

– up to the roll area limit ztta/roll_first,
– in the extended memory, up to the limit ztta/roll_extension or if extended memory is exhausted, then
– again in the roll area, until the roll area is full, then
– in the local process area, up to the limit abap/heap_area_dia or abap/heap_area_total or until the address space or the
swap space is exhausted.

What will be your action when all work processes are in the “running” status?

echtscorp Daily Administration, Performance Tuning

If only all Dialog work processes are running,

  • Check if there’s a number in the Semaphore column in SM50 or dpmon. If there is, click once on one of the numbers in the Semaphore column to select it and then, press F1 (help) to get a list of Semaphores. Then, search OSS notes and, hopefully, you’ll find a note that will tell you how to fix the problem.
  • If it’s not a semaphore (or sometimes if it is), use vmstat on UNIX or task manager on Windows to see if the operating system is running short on memory which would cause it to swap. In vmstat, the free column (which is in 4k pages on most UNIX derivatives) will be consistently 5MB or so and the pi and/or po columns will have a non- zero value. The %idle column in the cpu or processor section will be 0 or a very low single digit while the sys column will be a very high double-digit number because the operating system is having to swap programs out to disk and in from disk before it can execute them.
  • In task manager, look at free memory in the physical memory section under the performance tab. If it’s 10MB or 15MB (I think), then the operating system will be swapping.
  • when all the dialog work processes are running, you won’t be able to log in via SAPgui and will need to execute the dpmon utility at the commandline level. The procedure is basically the same on UNIX and Windows.

    • On UNIX:

    telnet to server and login as sidadm user.
    cd to /sapmnt/SID/profile directory
    execute “dpmon pf=SID_hostname_SYSNR” (e.g. PRD_hercules_DVEGMS00) select option “m” and then, option “l”

    On Windows:

    Click on START, then RUN
    Type “cmd” and press enter
    change to drive where profile directory resides (e.g. f:)
    cd to \sapmnt\SID\profile
    execute “dpmon pf=SID_hostname_SYSNR” (e.g. PRD_zeus_DVEGMS00) select option “m” and then, option “l”

  • Check for developer trace files in work directory at OS level.