Unfortunately, I do not have hyperthreading machine I can test OS/2 on. Or an SMP licence for that matter. But, I have been doing stuff under Windows.Windows 2003 server shows two CPUs when run on a machine with Hyperthreading. And turning it on does help. My job for the last 18 months has been testing software we develop. This is a development tool that generates source code from a model definition stored in SQLServer. There is a noticeable performance improvement when Hyperthreading is on compared to when it is not on. From memory it was better than 25% faster. This was happening because Windows could run SQLServer and our application on the real and virtual CPU and the total context swapping was less than when there was only the real CPU.
The interesting difference came with Pentium D machines. These have two cores and hyperthreading. On these machines, it was better to turn hyperthreading off. The problem was that Windows 2003 cannot tell the difference between the real and virtual processors. It would allocate SQLServer and our process to the real and virtual processors of the same physical processor. Turning off hyperthreading on these machines was getting us close to halving the single processor time.
OS/2 should benefit from hyperthreading. Because of the way that hyperthreading works, I would expect to see more improvement in a multi-threaded application than when running multiple single threaded processes. And OS/2 has always been good at multi-threading. Unfortunately, I can't think of a good test application. The old SETI@Home was a single thread application. I don't know about the BOINC version as I don't run it.
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David