Reinier Olislagers wrote:
Quick test on Linux x64 VM seems to show increasing to 8 (matching my # of physical cores, no hyperthreading on my CPU) does increase performance... using the famous unit of time called "number of cups of coffee I thought I drank while waiting for the compile"
Historically, 8 has been a bit of a limit on many different architectures. I don't know where this figure has come from, ultimately it could be something like a speed ratio between main memory devices and cache. Some of the larger systems have attempted to get round this limit by having multiple busses, e.g. 4x on the Cray CS6400 which was a precursor of the Sun E10K.
My tests suggest that the shape of the rolloff is OS-specific. IBM mainframes, of course, claim to vastly exceed anybody else's throughput, but I believe that they've got things like four-level cache as well as fibre-connected NUMA.
-- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] _______________________________________________ fpc-devel maillist - [email protected] http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
