Brian Gupta wrote: > http://www.theregister.co.uk/2007/07/26/sun_2048_thread_niagara/
Sounds like they noticed that the NCPU macro was recently raised from 64 to 256 for sun4v systems. "Also of note, we've discovered that Sun's next version of Solaris has been tweaked to handle up to 256 cores with an option to stretch all the way to 2048 cores. (Sun seems to be interchanging cores and threads at this point.)" The NCPU value is meant to be set to be one higher than the largest CPU ID value on the system so that it can be used, for example, to size arrays which will be indexed by CPU ID. On a Niagara based system with 8 cores and 4 "threads" per core, you would have CPU IDs ranging from 0 - 31, so NCPU would have to be at least 32. If, for example, you wanted to create a static array of pointers to each cpu_t structure on the system, you could do "cpu_t *my_cpu_array[NCPU]" and then index the array by CPU ID. For simplicity's sake, there are many places in the kernel that use NCPU to define data structures, despite that is not the most space efficient way to go for systems with less CPU "threads" or "strands" than NCPU. So if they are referring to the NCPU value, it doesn't represent the number of cores that OpenSolaris supports. All of that is really a mute point anyway because the NCPU value is set in some sun4u platform Makefiles to values over 500. Haik _______________________________________________ opensolaris-discuss mailing list opensolaris-discuss@opensolaris.org
