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Entry  29 Feb 2012, Konstantin Olchanski, Bug Report, Problem with semaphores 
    Reply  01 Mar 2012, Stefan Ritt, Bug Report, Problem with semaphores 
Message ID: 785     Entry time: 01 Mar 2012     In reply to: 784
Author: Stefan Ritt 
Topic: Bug Report 
Subject: Problem with semaphores 
> Anyhow, if anybody can suggest such an advanced locking library it would be great. Will save me the 
> effort of writing one.

Hi Konstantin,

yes there is a good way, which I used during development of the buffer manager function. Put in each sm_xxx function a cm_msg(M_DEBUG, ...) to 
generate a debug system message. They go only into the SYSMSG ring buffer and thus are light weight and don't influence the timing much. You can 
keep odbedit open to see these messages, but there is also another way. You can write a little program which dumps the whole SYSMSG buffer, which 
you can call when the lock happens. You then look "backwards" in time and get all messages stored there, depending of the size of the SYSMSG buffer of 
course. Of course this only works if the lock does not happen on the SYSMSB buffer itself. In that case you have to produce M_LOG messages which are 
written to the logging file. This will influence the timing slightly (the file might grow rapidly) but you are independent of semaphores.

The interesting thing is that in the MEG experiment (9 Front-ends, Event Builder, Logger, Lazylogger, ....) we run for months without any lock up. So I 
might suspect it's caused in your case from a program only you are using.

Best regards,
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