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From: diomidis@ecrcvax.UUCP (Diomidis Spinellis)
Newsgroups: comp.unix.questions
Subject: Re: Sun OS accounting file format
Summary: Interpretation of the accounting time fields
Keywords: accounting time acct comp_t
Message-ID: <737@ecrcvax.UUCP>
Date: 8 Jun 89 19:37:43 GMT
References: <1171@shell.shell.com>
Reply-To: diomidis@ecrcvax.UUCP (Diomidis Spinellis)
Organization: ECRC, Munich 81, West Germany
Lines: 55

In article <1171@shell.shell.com> dinah@shell.UUCP (Dinah Anderson) writes:
>We are trying to write our own program to create accouting reports.
>According to the man page, the data ytpe for some of the fields is:
>
> [ ... gives the manual description of comp_t ... ]
>
>Can someone help me understand how to interpret this field?

Comp_t is represented as a three bit base 8 exponent followed by a 13 bit
mantissa.  No normalisation takes place.  The place of the bits in the
u_short is as follows:

	+------+--------------------------+
	| exp  |        mantissa          |
	+------+--------------------------+
	 15  13 12                       0

Thus the value is: mantissa * 8 ** exponent and you can calculate it by:

(long)(val & 017777) << ((val >> 13) * 3)

>Also does anyone know what the units are for the fields :
>
>             comp_t   ac_utime;
This is the total amount of time the process spent executing in user
mode.

>             comp_t   ac_stime;
The total amount of time spent in the system executing on behalf of 
the process.

>             comp_t   ac_etime;
This is the time difference between the process creation (by fork) and
the process termination (by a signal or exit).  In other words the time
the process has existed.

The times are expressed in seconds / AHZ.  You have to divide by AHZ 
(defined in sys/acct.h) in order to get seconds.


>The man page does not say.
True.  You could get some info from getrusage(2).  With the abudance of
binary UN*X distributions the system source is no longer a viable
substitute for decent documentation.  It is becoming time for the
vendors to get their act together and produce more complete
documentation.

>Dinah Anderson 
Diomidis

-- 
Diomidis Spinellis          European Computer-Industry Research Centre (ECRC)
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