Re: Performance monitor signal handler

At 17:10 15/03/01 -0800, Alfred Perlstein wrote:
>> 
>> Which is why the backends should not do anything other than maintain the
>> raw data. If there is atomic data than can cause inconsistency, then a
>> dropped UDP packet will do the same.
>
>The UDP packet (a COPY) can contain a consistant snapshot of the data.
>If you have dependancies, you fit a consistant snapshot into a single
>packet.

If we were going to go the shared memory way, then yes, as soon as we start
collecting dependant data we would need locking, but IOs, locking stats,
flushes, cache hits/misses are not really in this category.

But I prefer the UDP/Collector model anyway; it gives use greater
flexibility + the ability to keep stats past backend termination, and,as
you say, removes any possible locking requirements from the backends.



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