Technical data

Since this is detached processing, a trace server process is created to write the

collected trace records to a trace ﬁle. By default, the name of this trace server

process is username$CTF, where username is your user name. You can specify

a different name for the trace server process by using the /PROCESS_NAME

qualiﬁer of the START command. By default, the trace server process writes

trace records to the ﬁle CTF$TRACE.DAT in your default directory. You can

specify a different trace ﬁle by using the /OUTPUT qualiﬁer of the START

command. For example:

CTF> START/OUTPUT=DDCMPTRACE.DAT "DDCMP LINK SYN-2"

collects trace records from the speciﬁed tracepoint and writes them to the ﬁle

DDCMPTRACE.DAT in your current directory.

See the description of the START command in Chapter 4 for a description of all

the qualiﬁers that you can use for detached tracing.

3.5.3 Starting Live Tracing

As with detached tracing (see Section 3.5.2), live tracing is controlled by the

START command. You start live tracing by including the /LIVE qualiﬁer in the

START command. For example:

CTF> START/LIVE "ROUTING CIRCUIT SYN-0"

starts collecting trace records from the speciﬁed tracepoint and displays them on

your terminal.

You can interrupt the display of trace records to enter CTF commands at any

time; for example, you may wish to enter CTF commands to change the format

of the display. To interrupt the display, simply press any key; the CTF> prompt

appears, and you can enter a CTF command. When the command has been

executed, the display of trace records is resumed. Any trace records generated

while you were entering a CTF command will have been buffered, and will be

displayed when the display of trace records is resumed. However, since buffer

space is limited, you may lose trace records if you leave the CTF> prompt

displayed for too long.

See the description of the START command in Chapter 4 for a description of the

qualiﬁers that you can use for live tracing.

3.5.4 Starting Snapshot Tracing

To start snapshot tracing, use the /NOCOLLECT qualiﬁer in the START

command. For example:

CTF> START/NOCOLLECT "ROUTING CIRCUIT SYN-1"

starts reading trace records from the speciﬁed tracepoint into the CTF buffer, but

does not write them to a trace ﬁle or display them on your terminal. When you

want to collect the contents of the CTF buffer, enter the following command:

CTF> COLLECT

If you are performing detached tracing, the current contents of the CTF buffer

are written to the default trace ﬁle, CTF$TRACE.DAT. You can then analyze the

contents of the trace ﬁle, as described in Section 3.6.2. If you are performing live

tracing, the current contents of the CTF buffer are displayed on your terminal.

Using CTF 3–7