On Wed, 27 Oct 2010 22:52:03 +0200, Andrew Brunner
<andrew.t.brun...@gmail.com> wrote:
My SCS project which is a scalable unified collaboration and
communication server that uses counting for transactions and network
consumption across all implemented protocols. Bytes, when aggregated
can clearly exceed the 2GB limitation within seconds. Partial
transactions (PTX) can exceed over 30,000 per second and full
transactions (TX) are typically 50% of that... But these numbers need
to add up. Meaning the aggregate TX count must be of some proportion
of the PTX otherwise they are bogus.
Int64 or QWord w/o locking or CAS is a serious issue for me. I
absolutely need this feature or my transaction/byte counts will be off
per node per cluster and can lead to misinformation in the consumption
reports.
Are you counting up only? Then you can use the 32-bit version of the
InterlockedIncrement on the lower word only. If this turns out to be zero
(the new value is returned) after the operation, you know you also have to
increment the high word. Even with 30'000 transactions per second it takes
about 9 hours until the lower word will be zero again, so the probability
of a race condition happening here is very close to zero.
Well, you still need to stop any reader from using the value while you do
that. Assuming that your read frequency is much lower than the number of
transactions per second, it shouldn't be a big problem to lock out the
reader for a couple of nanoseconds.
Vinzent.
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