From: jc@raven.bu.edu (James Cameron)
Newsgroups: comp.sys.sun.admin
Subject: Re: /usr/etc/chill
Date: 9 Apr 92 19:57:41 GMT
Organization: What do you mean 'That *can't* be done????'
In-reply-to: msirota@ee.rochester.edu's message of 7 Apr 92 19:15:53 GMT


Maybe someone should add this to the/a FAQ:

CHILL(8)              MAINTENANCE COMMANDS               CHILL(8)

NAME
     chill - remove useful pages from the virtual memory cache

SYNOPSIS
     chill [ -c cycles ] [ -f factor ] [ -m memsize ]

DESCRIPTION
     chill is a command designed to cool off the system by remov-
     ing  any useful (to a process) pages from the virtual memory
     cache.  chill does this by creating a large pool of  private
     pages,  and  then  cycling  through the pool, dirtying every
     page.  Currently, this forces chill's pages to be hot, which
     forces  out  all the other (non-locked) pages in the system.
     Then when chill exits, all its private pages are put on  the
     free list, leaving no useful pages in memory.

     With no options specified, the size of the pool  created  by
     chill  is  twice  the  amount  of pageable memory, and it is
     cycled through  just  once.   This  seems  to  give  correct
     results with minimal overhead.

     However, the size of the pool may be explicitly specified as
     memsize,  or  as factor times the amount of pageable memory.
     memsize overrides the factor specification.  The cycle count
     may be specified as cycles.

OPTIONS
     -c cycles
          Set the cycle count to cycles.  The default is 1.

     -f factor
          Set the expansion factor to factor.  The default is 2.

     -m memsize
          Set  the  memory  size  to  memsize.   The  default  is
          unspecified,  which  means that factor times the amount
          of pageable memory will be used.

BUGS
     chill is dependent on implementation details which are  sub-
     ject to change.


.\" @(#)chill.8 1.1 90/10/29 SMI;
.TH CHILL 8 "06 April 1988"
.SH NAME
chill \- remove useful pages from the virtual memory cache
.SH SYNOPSIS
.B chill
[
.B \-c
.I cycles
]
[
.B \-f
.I factor
]
[
.B \-m
.I memsize
]
.SH DESCRIPTION
.IX "chill remove" "" "\fLchill\fP \(em remove useful pages from virtual memory cache" ""
.IX "remove" "useful pages from cache"
.IX memory "remove useful pages from cache"
.IX "cool" "cool off system"
.LP
.B chill
is a command designed to cool off the system by removing any
useful (to a process) pages from the virtual memory cache.
.B chill
does this by creating a large pool of private pages,
and then cycling through the pool, dirtying every page.
Currently, this forces
.BR chill 's
pages to be hot, which forces out all the other (non-locked)
pages in the system.  Then when
.B chill
exits, all its private pages are put on the free list,
leaving no useful pages in memory.
.LP
With no options specified,
the size of the pool created by
.B chill
is twice the amount of pageable memory,
and it is cycled through just once.
This seems to give correct results with minimal overhead.
.LP
However, the size of the pool may be explicitly specified as
.IR memsize ,
or as
.I factor
times the amount of pageable memory.
.I memsize
overrides the
.I factor
specification.
The cycle count may be specified as
.IR cycles .
.SH OPTIONS
.TP
.BI "\-c " cycles
Set the cycle count to
.IR cycles .
The default is 1.
.TP
.BI "\-f " factor
Set the expansion factor to
.IR factor .
The default is 2.
.TP
.BI "\-m " memsize
Set the memory size to
.IR memsize .
The default is unspecified, which means that
.I factor
times the amount of pageable memory will be used.
.SH BUGS
.LP
.B chill
is dependent on implementation details
which are subject to change.
--
					-- James Cameron  (jc@raven.bu.edu)

Signal Processing and Interpretation Lab.  Boston, Mass  (617) 353-2879
------------------------------------------------------------------------------
"But to risk we must, for the greatest hazard in life is to risk nothing.  For
the man or woman who risks nothing, has nothing, does nothing, is nothing."
	(Quote from the eulogy for the late Christa McAuliffe.)
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