PWAIT$SDA is a SDA extension (using the API first documented for VMS V7.2) which displays information about a process waiting and what it is waiting for. PWAIT$SDA can be used to look at a crash dump or at a running system. PWAIT$SDA is intended to help investigating why a process appears hung. PWAIT$SDA has been built on OpenVMS Alpha (V7.2->V8.2) and OpenVMS Itanium. INSTALLATION ------------ Copy the supplied PWAIT$SDA.EXE for your version of VMS to SYS$SHARE: or define the logical name PWAIT$SDA to point to the file. e.g for OpenVMS Alpha V7.3-2 $ DEFINE PWAIT$SDA dev:[dir.subdir]PWAIT$SDA.EXE_ALP_V732 TO USE ------ When analyzing a crash dump or the current running system using SDA enter the command PWAIT (at the SDA> prompt) and information will be displayed about the currently selected process. The currently selected process is the process most recently displayed with SHOW PROCESS or the current process in a crash or the process selected with SET PROCESS. To look at process with pid 321 PWAIT /ID=321 To look at the process named SERVER PWAIT SERVER The information displayed varies depending on the process state. For example :- (the following list is not intended to list everything that PWAIT displays). LEF/CEF - the number of the event flag(s) - the local event flags and common event flags (if relevent) - the active I/O channels and related I/O requests - the timer requests for this process JIBWAIT i.e. waiting a pooled quota such as BYTLM - name of quota and initial and current values RWAST - name of quota (if BIOLM/DIOLM appears to be 0) - pc at which process is waiting - address of the caller (which can indicate the possible reason for the RWAST) - active channels (in some cases) RWMBX - name of mailbox that process is waiting for space in (on Alpha only) MUXTEX - address of mutex inc related symbolic name if known Examples ! looking at crash $ ANALYZE/CRASH SYS$SYSTEM:SYSDUMP.DMP SDA> CLUE CRASH ! get the basic info SDA> PWAIT ! look at the current process $ ANALYZE/SYSTEM SDA> SHOW SUMMARY ! get list of processes to find pid SDA> PWAIT/IN=10C ! look at process with id 10c AUTHOR ------ This program was written by Ian Miller. Bug reports and comments to miller@encompasserve.org CHANGES ------- V0.1 Initial version. V0.2 more info V0.3 For RWMBX try and workout which mailbox V0.4 Look at Kernel Thread Blocks instead of PCB, various tidy up V0.5 Display active channels. Allow specification of process. V0.6 Display some IRPs V0.7 Display Timer Queue and how long process has been waiting V0.8 Fix build on VMS V7.2-1 V0.9 Add changes suggested by Richard Whalen of Process Software for building pwait$sda on Itanium VMS. A couple of other small changes. V0.A Fix bug in handling of processing with more than one kernel thread. Fix bug in display of some mwait states. If process is waiting for a know static mutex display its name. Display active channels and TQE list for HIB processes. Some cosmetic changes to displays. V0.B Show the deaccess irp if there is one. Display some suggestions about other resource wait states. V0.C Display the inner mode semphore for kthreads waiting for it. V0.D Better analysis including looking at the return address. Fixed some more bugs. Analyze context wait (used by Fast I/O et al). When displaying TQE display only wakeup ones for HIB process and for LEF process match waiting EF. V0.E Display I/O's for mailbox and disk. Various other improvements. V0.F Display how long process has been waiting (thanks to Volker Halle). V0.G Analyze FPG. Analyze locks. Various bug fixes. (thanks to Volker Halle). V0.H If process waiting for sub-process to die then display names of sub-process. If process in mutex wait then display names of processes that own mutexes. V1.0 Lots of improvements to analysis, lock tracing etc. TO BUILD -------- A C compiler is required. I usually use DEC C V7.1 @B_PWAIT$SDA.COM COPYRIGHT NOTICE ---------------- This software is COPYRIGHT © 2004, Ian Miller. ALL RIGHTS RESERVED. This software is released under the licence defined below. 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