02/26/85  post_purge_meters, ppm

Syntax as a command:  ppm {-control_arg}


Function:  displays information collected at post purge time, if post
purging is enabled.  The print_tuning_parameters and work_class_meters
commands (described later in this section) are used to determine which
work classes, if any, are being post purged.


Control arguments:
-reset, -rs
   resets the metering interval for the invoking process so that the
   interval begins at the last call with -reset specified.  If -reset
   has never been given in a process, it is equivalent to having been
   specified at system initialization time.
-report_reset, -rr
   generates a full report and then performs the reset operation.


Access required:  This command requires access to phcs_ or
metering_gate_.


Notes:  If the post_purge_meters command is given with no control
argument, it prints a full report.

The following is a brief description of each of the variables printed
out by the post_purge_meters command.
Post purge time
   is the average CPU time per post purge call.
Ave list size
   is the average number of page fault entries found in the per-process
   page trace list at post purge time.


Ave working set
   is the average estimated working set.  The current estimated working
   set for each process is computed by the following formula.

         working set = working_set_factor * raw_working_set
         + working_set_addend

   The raw working set is estimated by page control at post purge time.
Working set factor
   is the current value of the wsf tuning parameter, and can be changed
   by the change_tuning_parameters command.  Increasing the value tends
   to reduce page thrashing, but may increase multiprogramming idle.
   Decreasing the value has the opposite effects.


Working set addend
   is the current value of the wsa tuning parameter, and can be changed
   by the change_tuning_parameters command.  Increasing and decreasing
   this value has the same effects as noted above.
Thrashing percentage
   is the percentage of page faults that were taken on pages faulted
   earlier in quantum.
Ave post in main memory
   is the average number of entries in the trace list for which the
   page was still in main memory at post purge time, and the ratio of
   incore pages to faulted pages expressed as a percentage.


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Historical Background

This edition of the Multics software materials and documentation is provided and donated
to Massachusetts Institute of Technology by Group BULL including BULL HN Information Systems Inc. 
as a contribution to computer science knowledge.  
This donation is made also to give evidence of the common contributions of Massachusetts Institute of Technology,
Bell Laboratories, General Electric, Honeywell Information Systems Inc., Honeywell BULL Inc., Groupe BULL
and BULL HN Information Systems Inc. to the development of this operating system. 
Multics development was initiated by Massachusetts Institute of Technology Project MAC (1963-1970),
renamed the MIT Laboratory for Computer Science and Artificial Intelligence in the mid 1970s, under the leadership
of Professor Fernando Jose Corbato. Users consider that Multics provided the best software architecture 
for managing computer hardware properly and for executing programs. Many subsequent operating systems 
incorporated Multics principles.
Multics was distributed in 1975 to 2000 by Group Bull in Europe , and in the U.S. by Bull HN Information Systems Inc., 
as successor in interest by change in name only to Honeywell Bull Inc. and Honeywell Information Systems Inc. .

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Permission to use, copy, modify, and distribute these programs and their documentation for any purpose and without
fee is hereby granted,provided that the below copyright notice and historical background appear in all copies
and that both the copyright notice and historical background and this permission notice appear in supporting
documentation, and that the names of MIT, HIS, BULL or BULL HN not be used in advertising or publicity pertaining
to distribution of the programs without specific prior written permission.
    Copyright 1972 by Massachusetts Institute of Technology and Honeywell Information Systems Inc.
    Copyright 2006 by BULL HN Information Systems Inc.
    Copyright 2006 by Bull SAS
    All Rights Reserved