View source for MONITOR MPLOCK command

==Summary==
<dl>
<dt>Privileges
<dd>System administrator
<dt>Function
<dd>You can display information about <var class="product">Model&nbsp;204</var> multiprocessor lock contention. The command output is mainly intended for Rocket Software Technical Support.
</dl>
==Syntax==
<p class="syntax"><b>M</b>ONITOR MPLOCK
</p>
==Example==
Your output might look similar to the following:
<p class="code"><b>MONITOR MPLOCK</b><nowiki>
Name   Usage       Spins    Waits    Posts
----   -----       -----    -----    -----
NONE                                       no contention
SIR1                                       no contention
SIR2                                       no contention
ITS1                                       no contention
ITS2                                       no contention
USR1                                       no contention
USR2                                       no contention
TST1                                       no contention
TST2                                       no contention
ECTM                                       no contention
ECMM                                       no contention
MQCH                                       no contention
MQST                                       no contention
MQTA                                       no contention
HASH    DKDP           6        1
        DKFB          79       78       93
        DKFR          32       25
        DKSW          91       45       56
LRUQ    DKUC          90        1
        DFB1           3        1
        DFB2          67        2        2
        DFR2           1
RCLK                                        no contention
FORT                                        no contention
V7IB                                        no contention
V7OB                                        no contention
QMAN                                        no contention

QUEU                                        no contention
DBCD    DKUC           1
        DU2L           4        2        1
        DKRR           2        1
        DKFB                             2
FILD                                        no contention
TWND                                        no contention
CMLW    CDEQ           1
PAGE                                        no contention
CNST                                        no contention
SMFS                                        no contention
JRNL    BUFF           3
</nowiki></p>

==Usage==
<p>For each lock, separate counts are maintained for each use of the lock-meaning, for each purpose for which the lock can be requested). </p>
<table>
   
<tr> <th>
<p>Output column </p>
</th> <th>
<p>Indicates...</p>
</th> </tr>
   
<tr> <th><var>
<p>Name </p>
</var></th> <td>
<p>Lock name</p>
</td> </tr>
 
<tr> <th><var>
<p>Usage </p>
</var></th> <td>
<p>Usage names per lock name</p>
</td> </tr>
 
<tr> <th><var>
<p>Spins </p>
</var></th> <td>
<p>Number of times that there was contention for the lock, and the requesting task was able to obtain the lock within MAXSPINS spins.</p>
</td> </tr>
 
<tr> <th><var>
<p>Waits </p>
</var></th> <td>
<p>Number of times that there was contention, and the requesting task had to enter a WAIT for the lock.</p>
</td> </tr>
 
<tr> <th><var>
<p>Posts </p>
</var></th> <td>
<p>Number of times that a task released a lock, and there was a waiting task to be posted.</p>
</td> </tr>
 
<tr> <th><var>
<p>(unlabeled) </p>
</var></th> <td>
<p>If there is no contention for the lock</p>
</td> </tr>
   
</table>
<p>All numbers are cumulative since the beginning of the run. The lock names and usage names relate to <var class="product">Model&nbsp;204</var> internals only.</p>
<p>When you run <var class="product">Model&nbsp;204</var> with the MP/204 (multiprocessor) option, the <var class="product">Model&nbsp;204</var> nucleus uses a number of locks to control access to shared memory resources. For each lock, the output indicates the number of times since <var class="product">Model&nbsp;204</var> started that contention for the lock occurred. Contention means that one task attempted to acquire the lock, but could not because another task was holding the lock at the time. </p>
<p>If you issue a MONITOR MPLOCK command, but are not running MP/204, the following message is displayed: </p>
<p class="code">M204.1925: MPLOCK OPTION REQUIRES NMPSUBS>0
</p>
[[Category: System administrator commands]]
[[Category:Commands]]