TSCSKEWD

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Section: Active Probing Manual (8)
Updated: Wed Mar 13 2003
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NAME

tscskewd - a program for calculating the current tsc conversion constant  

SYNOPSIS

tscskewd [OPTION]...  

DESCRIPTION

tscskewd is a daemon process that runs in the background and can be used to set a fixed TSC conversion contstant and offset estimate or it can be set to continously estimate the current TSC conversion constant using the standard SW clock (gettimeofday()) which should be and is assumed to be synchronised to a primary NTP server. The default parameters of the TSC skew daemon assume max. 2ms offset in the NTP synch. SW clock

tscskewd is typically started at system startup using the init scripts in /etc/init.d/tscskew and defaults to continually estimating the TSC conversion constant by assuming that the computer is synchronised to a NTP server with max. 2ms offset.

This program sets up a shared memory segment in order to convey the conversion constant to any interested user processes. The program readtscskew can be used to read these values or they can be accesses directly in a program by accessing the shared memory segment.

Using the command line options it is possible to fix the values that tscskewd reports instead of having the program continually estimating the value. The command line switches are as follows:

-c, --count

This specifies a value for the number of CPU cycles counted

-f, --foreground

force the tscskewd process to run in the foreground instead of automatically backgrounding itself, as it does by default. This also produces some more output

-n, --ntp

this is the default operation of tscskew. It assumes the computer is synchronised to a NTP server and continually estimates the conversion constants

-o, --offset

this specifies a value for the offset

-t, --time

this specifies a value for the time in microseconds

 

EXAMPLES

tscskewd -c5383534886 -t12000010 -o0

Run the daemon with fixed values for count, time and offset.

tscskewd -n

Run the daemon so that it continually produces conversion constant estimates

tscskewd --foreground

Run the daemon so that it continually produces conversion constant estimates and run it in the foreground

 

SEE ALSO

More information about the accuracy of TSC timing methods can be found by looking at the CUBINlab website. Visit <http://www.cubinlab.ee.unimelb.edu.au/probing/> for articles and complete up-to-date active probing software packages.

readtscskew(1), tscreceiver(8), tsclinuxSend(8), tsclinuxps(8).

 

AUTHORS

Created by: Attila Pasztor <attila@cubinlab.ee.unimelb.edu.au>,
Updated by: David Smith    <djps@cubinlab.ee.unimelb.edu.au> and
            Campbell Skene <crsk@cubinlab.ee.unimelb.edu.au>

 

REPORTING BUGS

Report bugs/comments to the CUBINlab Probing Team <http://www.cubinlab.ee.unimelb.edu.au/probing/>.  

COPYRIGHT

Copyright © 2003 Attila Pasztor, David Smith, Campbell Skene. Distributed under GPL. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

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Index

NAME

SYNOPSIS

DESCRIPTION

EXAMPLES

SEE ALSO

AUTHORS

REPORTING BUGS

COPYRIGHT

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This document was created by man2html, using the manual pages.
Time: 04:17:56 GMT, March 14, 2003