T3, T4, T5, Threads, Architecture, and Solaris
Thanks for a very good article, TPM!
[TPM] Fowler said that the current Solaris 10 tops out at 512 threads and a few terabytes of addressable main memory.
I found that an interesting statement since 16 cores * 8 threads * 4 sockets = 1024 threads - with Solaris 10 is performing linearly, for the most part, in most benchmarks. I think there is more to this.
[TPM] It is therefore not a coincidence that last year's top-end Sparc T3-4 server, which had eight 16-core, 128-thread Sparc T3 processors topped out at four sockets.
Adding 8 sockets onto the new T4 would mean Solaris would have to manage the same number of threads that Solaris is handling today with the T3 - so I don't really think this the socket limitation with T processors is a Solaris "threads" related issue. The math just does not suggest this conclusion.
I suspect the sockets limits had more to do with the complexities of adding an additional bit to the SMP glue. More complete thoughts are here.
[TPM] To be fair, Oracle could no doubt have patched Solaris 10 to extend its thread count a little
You are absolutely correct. Many threading enhancements were added to Solaris 10 Update 10. Oracle could, and they did.
[TPM] Solaris 11 will, for instance, have one button rollback features so if customers don't like the results of their upgrade to Solaris 11
Live Upgrade has existed in Solaris for years - fast and simple upgrade with a keystroke and rollback with a keystroke using a mirror was something fairly unique to Solaris. OpenSolaris with ZFS took it a step forward, some years ago. I don't think this added any delay. The backport of this feature into Solaris 10 really takes Solaris 10 light-years ahead. Fowler might be talking about the ZFS timeslider...
I really don't think that Solaris 11 was planned to be released in 2011-11 because of difficulties with these features for Oracle RDBMS integration. I think there are a lot of other "better" reasons.
This was a thoughtful article, nice writing!