For those that are interested in the effect of multi-CPU's and
hyperthreading has with an IMail/Declude setup, here's some additional
research.
I previously tested my dual Xeon setup with both hyperthreading enabled
and disabled, and found that the utilization jumped an astonishing ~100%
when I disabled hyperthreading. I figured that there was a decent
chance that this could be unique to my server. Upon testing Nick's own
server with an almost identical configuration I again found a jump of
~100% in utilization when hyperthreading was disabled. FYI, I'm sure
that the stats are correct and not an issue with the stats gathering
mechanism because my server was being pummeled and was bogged down
appropriately when it was at high CPU. The attached graphs show the
effect of having hyperthreading both on and off on two different servers.
I assume from these confirmed results that with only two CPU's
recognized by the system instead of 4 CPU's when hyperthreading is
enabled, the system gets bogged down in managing the threads/processes,
and this is what causes it to lose significant performance. This also
strongly suggests that as utilization rises due to adding more E-mail
volume, the efficiency may fall. I have noted that my system when
recovering from a backup in E-mail does not seem to catch up very
quickly even when pegged at 100%. Judging by the performance at 50% or
lower utilization, I would have expected a redlined server to handle
more. On both my system and Nick's systems we run at least 3 external
tests and two virus scanners as well as many Declude filters, and I
suspect that it is the command line stuff that contributes to this
negative effect.
Both of us are running on a SuperMicro platform, so that can't be ruled
out as a culprit, and we are also both running Declude 2.0.x. I am
willing to test another system on a different platform that is running
Declude 3.x just to confirm whether or not this caries over to the
modified processes.
So the rule of thumb here, if this research is accurate, is that
hyperthreading is a huge benefit to Declude, and it should follow that
having as many physical and virtual CPU's as possible is much more
important than maxing out the CPU speed. Quite literally, a single
hyperthreaded 3GHz CPU is as good as two 3GHz CPU's with no hyperthreading.
Matt
