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Scripts

Introduction

In this section the various scripts which are contained in this package are described. For the ease of the reader they are classified in the following categories:

Test scripts
The main scripts which are executing the network performance tests at the control host and at the test hosts.

Test help scripts
There are help scripts which are invoked by the main measurement scripts.

Server / client scripts
These scripts may be used for the remote invocation from the net performance scripts at the test client hosts. They may form a replacement for the remote or secure shell.

User scripts
These scripts can be invoked by the user for some additional tasks.

More information about the scripts described in this section can be obtained from:

Test scripts

These scripts are the main scripts which are performing the network tests at the control and test hosts. There are the following measurement scripts:

net_test_hosts_ext
This script executes the network performance measurements at the control host for a hosts set with a particular hosts extension. Please note that the hosts extension hosts_ext will be defined during the installation of the corresponding hosts set. See install.html for more information. This script contains the parameters, specified during the installation procedure, that are specific for this hosts set. It invokes the script net_test, specifying these parameters with the script arguments, to perform the real network performance tests. Besides these tests also some extra tasks are dome by this script such as truncation of the log files.

net_test
This script actually performs the network performance measurements conform to the scheme which is displayed in the measurement procedure figure. For all tests hosts from this figure, the following scripts are executed in two successive loops:
  1. Check if the net performance servers, listed below, are properly running. They are (re)started when this is not the case.
    • The script start_netserver is used to check the netserver daemons that are needed for the throughput measurements.
    • When UDP bandwidth measurements from the UDPmon package are selected in the hosts setup, the start_udpmon_resp script will check the udpmon_resp server that is used for these tests.
  2. The script host_net_test is invoked with a remote shell to process the measurements at that host i. The test parameters (a.o. the destination hosts of the tests) are also specified with the script arguments. It stores the measurement values, obtained from the Standard Input of host_net_test, in the appropriate data structures.

start_netserver
This script checks if the netserver daemon from the Netperf package is running at the local host. It is started when this is not the case. Also multiple instances from a running netserver are killed. They are often introduced by a network failure. In general these processes do not disappear anymore without intervention.

start_udpmon_resp
This script checks if the start_udpmon_resp daemon from the UDPmon package is running at the local host. It is started when this is not the case. Also multiple instances from a running udpmon_resp server are killed.

host_net_test
This script performs the network performance measurements from the local host to the specified destination hosts specified in the arguments. Also the test parameters are specified with the argument vector. The results are listed to the Standard Output.

Test help scripts

These scripts are used by the main measurement scripts for auxiliary tasks. They are less important. Therefore, they are described briefly here. More information can be found in the (HTML) manual pages.

get_user_pids
This script is used by net_test_hosts_ext if another instance of the performance measurements is already running.

timeout_command
This script is used by net_test_hosts_ext to set a timeout for various remote commands started by this script.

redir_file
This script is used by net_test_hosts_ext in the exceptional situation that the test data files must be copied to another host. A reason may be that there is no Web server at the control host, while, due to a firewall, there is not other host available to do the tests.
See the comment headers in the configuration template
InstallRoot/config/config.mk
for more information. The directory InstallRoot is the directory you used to install this package.

untar_dir
This script is also used for the copying of the test data from the control host to another host. It is used for the copying of the data directories, while redir_file, listed above, is used for the copying of the data files.

Server / client scripts

These scripts may be used for the remote invocation from the net performance scripts at the test client hosts invoked by the control host. The following scripts are available:

net_test_com_server
This server script is used at the test client hosts to start the net performance tests at that host and report the results to the control host.

start_net_test_com_server
This script is used to start the net_test_com_server server at the test client host when it does not yet run.

rem_net_test_com
This client script is used by the control host to start the net performance tests at the appropriate test host and to receive the reports from the net_test_com_server server at that test host.

User scripts

Besides the scripts, used to execute the network performance measurements, there are also scripts available to offer extra functionality to the user. These scripts are described below.

log_hosts_ext
This script can be used to follow the log file from the net performance tests at the control host for the hosts set with the hosts extension hosts_ext. When xtail is installed at your system, also the crontab log file is followed. In a X Windows environment a new xterm terminal emulator is used for the logging. This script may be useful for checking the status of the monitor.

net_test_mean_hosts_ext
This script can be used to recalculate the mean data files for the hosts set configuration with the hosts extension hosts_ext. The mean data files of the performance monitor are periodically updated. This implies that there is a reasonable chance that they may become corrupted. A cause for corruption may be irregularities in the monitor due to network problems. However, a stable factor in the monitor is the week data files: a week data file stays unchanged when the corresponding week is ended. Therefore, the week data files are used at the recalculation of the mean data files.
See also the discussion in the "Measurement Strategy" section.
The real calculation is done by the net_test_mean script. However, the usage of this script is more convenient because all appropriate arguments are specified by it in the correct form to net_test_mean.

net_test_mean
This script can be used to recalculate the mean data files. However, do not use it directly but use the net_test_mean_hosts_ext script instead: that script contains the required arguments in the correct form to recalculate the mean data files for the hosts set with hosts extension hosts_ext.

mean_time_net_test
The Web pages contains various data files where the mean values are calculated as a function of the hours of the day where the data were measured. See also the description of the data files. This script makes it possible to make a more precise definition of the domain where the mean time data are calculated. The mean values can be calculated for the throughput and round-trip values. The domain can be specified with the following attributes
The script list_net_test_weeks can be used to translate a week interval, in which the mean values should be calculated, into week numbers in a form suited to specify to this script.
Besides calculating mean values this script can also determine the minimum and maximum values at the hours of the day.

hist_net_test
This script calculates a histogram from the weekly data files. The histogram will be calculated for the connection from a source host to a destination host. The histogram can be calculated for the throughput and round-trip values. Also here the script list_net_test_weeks can be used to translate week intervals into week number options which are suited to supply to this script.

event_net_test
This script lists net performance events which are specified using Perl regular expressions. The throughput and round-trip values may be used in these expressions. Also here the script list_net_test_weeks can be used to translate week intervals into week number options which are suited to supply to this script.

list_net_test_weeks
This script lists the information of the weeks from which the data are stored for a particular host set. Optionally also the hosts can be listed which are participating in the tests for a particular week. Alternatively, when a week interval rate is specified, the available weeks can be grouped in a form suited to other scripts from this package. For instance this can be used to calculate the mean values for all data obtained in a particular week interval rate, using the script mean_time_net_test.

sed_net_data
This script executes the stream editor sed at all net data files in the net data directory tree.
Please note that the data files can become corrupted when you make an error. Therefore, follow the instructions in the "WARNING" section of the sed_net_data(1) man page.

update_net_data_headers
This script updates some fixed header values in all net performance data files with the values from the configuration files. This is especially useful when you made a change to a configuration file.
Please note that the data files can become corrupted when you make an error. Therefore, follow the instructions in the "WARNING" section of the update_net_data_headers(1) man page.

net_load
This script can be used to determine the various routes between sites participating in this package. Also the network load at these routes, induced by the traffic generated at the participating sites, can be calculated.
See also the "Net load" sub section contained in the "Description" section of this manual.


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