On Sun, Mar 19, 2006 at 10:38:36AM +0100, [EMAIL PROTECTED] wrote: > > >I didn't try this on a laptop, but here are some numbers from a 2-way > >AMD system running in 64-bit mode showing how much memory gets used by > >the > >kernel in each case. > > > >NCPU max_ncpus kernel > >64 2 227MB > >21 21 231MB - stock Nevada bits > >64 32 233MB > >64 64 242MB > > Wow; that is quite a bit more than I expected (the strange "21" number > comes from ancient times when apparently 21 "sizeof (struct cpu)" fitten > on (a multiple of?) a page. > > >So if max_ncpus is set to 64, we'd be throwing away 10Mb (or ~5% of > >all memory on a 256Mb laptop). The difference between 21 and 32 is > >much smaller. > > So what exactly uses this 256KB per CPU?
kmem cpu caches are about 20k/cpu (64 bytes/cpu/cache * ~300 caches * max_ncpu) FMA looks like it's about 100k/cpu (ERPT_MAX_ERRS * max_ncpu * ERPT_DATA_SZ) Cheers, - jonathan > Casper > _______________________________________________ > opensolaris-discuss mailing list > [email protected] -- Jonathan Adams, Solaris Kernel Development _______________________________________________ opensolaris-discuss mailing list [email protected]
