strace(1M)        MISC. REFERENCE MANUAL PAGES         strace(1M)



NAME
     strace - print STREAMS trace messages

SYNOPSIS
     strace [ mid sid level ] ...

DESCRIPTION
     strace without arguments writes all STREAMS event trace mes-
     sages  from  all drivers and modules to its standard output.
     These messages are obtained  from  the  STREAMS  log  driver
     [log(7)].   If  arguments  are provided they must be in tri-
     plets 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

          <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  ter-
     minated by the user.

EXAMPLES
     Output all trace messages from the module  or  driver  whose
     module ID is 41:

          strace  41 all all Output  those  trace  messages  from
          driver/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.




            Last change: Networking Support Utilities           1

strace(1M)        MISC. REFERENCE MANUAL PAGES         strace(1M)



SEE ALSO
     log(7)
     Programmer's Guide: STREAMS

NOTES
     Due to performance considerations, only one  strace  process
     is  permitted to open the STREAMS log driver at a time.  The
     log driver has a list of the triplets specified in the  com-
     mand  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 tri-
     plets will have a greater impact on overall STREAMS  perfor-
     mance.  Running strace will have the most impact on the tim-
     ing 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,
     then  some of the messages will be lost.  This last case can
     be determined by examining the sequence numbers on the trace
     messages output.




































            Last change: Networking Support Utilities           2