Hello,

On the 5 minute mark...
I just downloaded the cvs after burton posted the fix and it all re-compiled 
fine.

I notice that the "network load statistics" graph only shows data for 5 
minutes. It changes every minute but only shows the last 5 minutes.... at the 
right of the graph.

????

Earl

On Friday 13 December 2002 15:20, Burton M. Strauss III wrote:
> There are a couple of reports (and both Luca and I have seen the problem
> across a range of OSes) with ntop deadlocking.  The symptom is that the web
> server is up, but no packets are being processed, so the counts don't
> change.  It happens on the 5 minute mark, i.e. related to idle purge.
>
> Clearly, part of the problem was my performance change in hash.c for the
> idle purge of large networks.  I've finally found the problem (operator
> precedence) and so I believe I've closed that problem.  That fix is now in
> the cvs (if you track my stuff, it's refs 178 and 179).  This code will be
> in the snapshot of 14Dec2002.
>
> It should be VASTLY better.
>
> However, I've still seen ntop deadlock with that fix in.  Just much, MUCH
> less frequently.
>
>
> Over the past couple of days, I've put a couple of enhancements in to try
> and trap these things.
>
> 1) info.html (and textinfo.html) now report "blocked" mutexes.
>
> A single instance of a "blocked" mutex is NOT a problem (mutexes do block
> now and then).
>
> However, if it doesn't clear after a few seconds, that IS a problem.  Best
> way to check is to refresh and see if the # of locks/unlocks grow.
>
>
> 2) Frees of unlocked mutexes are reported:
>
> WARNING: releaseMutex() call with an UN-LOCKED mutex [%s:%d]
>
>
> 3) self-LOCKING is reported:
>
> WARNING: accessMutex() call with a self-LOCKED mutex [from pbuf.c:1719
> processPacket, locked by processPacket]
>
> This is where a thread locks a mutex that it has already locked.  Note that
> this warning is imperfect - the fields ntop uses are added onto the POSIX
> Pthread mutex structure.  There's no way to make the added code atomic w/o
> single threading ntop, so the simple minded wrapper I've put in place may
> give spurious results.
>
> It does not impact the functioning of ntop, it is just a log message.
>
>              What I'm saying is, "DON'T PANIC".
>
> If ntop does deadlock (i.e. no packets being processed and the # of
> locks/unlocks doesn't grow), then the WARNING may explain why.
>
> But, if you see the warning and ntop doesn't deadlock, well, then it was
> just the way things got run.
>
> If you're running ntop capturing from more than one network card, it's more
> likely to see a spurious message because there are two packet capture
> threads and (right now), the lock "keys" are the same.  Adding the pid to
> the lock stuff would fix that, but the focus is on the deadlock, not the
> cosmetics.  Especially if it's a busy network.
>
> If your ntop locks up and you have pulled hash.c revision 2.108 from the
> cvs (that is after
> 13Dec2002 18:50:48 in Pisa - 12:50:48pm US Central Time), please find the
> lines from the log and report them on ntop-dev.
>
>
> -----Burton
>
>
>
>
>
> _______________________________________________
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