STRACE(8) Maintenance Commands and Procedures STRACE(8)

NAME

strace - print STREAMS trace messages

SYNOPSIS

strace [mid sid level]...

DESCRIPTION

strace without arguments writes all STREAMS event trace messages from
all drivers and modules to its standard output. These messages are
obtained from the STREAMS log driver (see log(4D)). If arguments are
provided, they must be in triplets of the form mid, sid, level, where
mid is a STREAMS module ID number, sid is a sub-ID number, and
level is a tracing priority level. Each triplet indicates that
tracing messages are to be received from the given module/driver,
sub-ID (usually indicating minor device), and priority level equal
to, or less than the given level. The token all may be used for any
member to indicate no restriction for that attribute.


The format of each trace message output is:


<seq> <time> <ticks> <level> <flags> <mid> <sid> <text>

<seq>
trace sequence number


<time>
time of message in hh:mm:ss


<ticks>
time of message in machine ticks since boot


<level>
tracing priority level


<flags>
E : message is also in the error log F : indicates a fatal
error N : mail was sent to the system administrator
(hardcoded as root)


<mid>
module ID number of source


<sid>
sub-ID number of source


<text>
formatted text of the trace message


Once initiated, strace will continue to execute until terminated by
the user.

EXAMPLES

Example 1: A sample output of the strace command:

The following example outputs all trace messages from the module or
driver whose module ID is 41:


strace 41 all all


The following example outputs those trace messages from driver or
module ID 41 with sub-IDs 0, 1, or 2:


strace 41 0 1 41 1 1 41 2 0


Messages from sub-IDs 0 and 1 must have a tracing level less than
or equal to 1. Those from sub-ID 2 must have a tracing level of 0.

SEE ALSO

log(4D), attributes(7)

NOTES

o There is no restriction to the number of strace processes
opening the STREAMS log driver at a time.

o The log-driver records the list of the triplets specified
in the command invocation, and compares each potential
trace message against this list to decide if it should be
formatted and sent up to the strace process. Hence, long
lists of triplets will have a greater impact on overall
STREAMS performance. Running strace will have the most
impact on the timing of the modules and drivers
generating the trace messages that are sent to the strace
process. If trace messages are generated faster than the
strace process can handle them, some of the messages will
be lost. This last case can be determined by examining the
sequence numbers on the trace messages output.

October 4, 1994 STRACE(8)