IBM AIX Continuous Availability Features - IBM Redbooks
IBM AIX Continuous Availability Features - IBM Redbooks
IBM AIX Continuous Availability Features - IBM Redbooks
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Trace is a valuable tool for observing system and application execution. Where other tools<br />
provide high level statistics such as CPU utilization or I/O wait time, the trace facility is useful<br />
in expanding the information to understand the who, when, how, and why of an event.<br />
Single thread trace<br />
In prior versions of <strong>AIX</strong>, system trace would trace the entire system. In <strong>AIX</strong> V5.3, the system<br />
trace facility has been enhanced by new flags. This enables the trace to run only for specified<br />
processes, threads, or programs. The system trace can be used to trace the processor<br />
utilization register (PURR) to provide more accurate event timings in a shared processor<br />
partition environment.<br />
Administrative control of the user trace buffers<br />
Also, in previous versions of <strong>AIX</strong>, the trace buffer size for a regular user is restricted to a<br />
maximum of 1 MB. Version 5.3 allows the system group users to set the trace buffer size<br />
either through a new command, trcctl, or using a new SMIT menu called Manage Trace:<br />
smitty trace → Manage Trace<br />
To check the actual trace subsystem properties, use the trcctl command, as shown in<br />
Example 2-2.<br />
Example 2-2 Trace characteristics<br />
lpar15root:/root#trcctl<br />
Default Buffer Size: 262144<br />
Default Log File Size: 2621440<br />
Default Log File: /var/adm/ras/trcfile<br />
Non-Root User Buffer Size Maximum: 1048576<br />
Default Components Directory: /var/adm/ras/trc_ct<br />
Default LMT Log Dir: /var/adm/ras/mtrcdir<br />
To list all trace event groups, you can use the following command:<br />
trcevgrp -l<br />
There are several trace-related tools which are used for various operating system<br />
components:<br />
► CPU monitoring tprof, curt, splat, trace, trcrpt<br />
► Memory monitoring trace, trcrpt<br />
► I/O subsystem trace, trcrpt<br />
► Network iptrace, ipreport, trace, trcrpt<br />
► Processes and threads tprof, pprof, trace, trcrpt<br />
Trace can be used in two ways: interactively, or asynchronously, as explained here:<br />
► Interactively<br />
The following sequence of commands runs an interactive trace on the program myprog<br />
and ends the trace:<br />
trace -j30D,30E -o trace.file<br />
->!myprog<br />
->q<br />
28 <strong>IBM</strong> <strong>AIX</strong> <strong>Continuous</strong> <strong>Availability</strong> <strong>Features</strong>
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