Path: utzoo!attcan!uunet!husc6!mailrus!ames!oliveb!sun!gorodish!guy From: guy@gorodish.Sun.COM (Guy Harris) Newsgroups: comp.unix.wizards Subject: Re: Vax 11/780 performance vs Sun 4/280 performance Message-ID: <55019@sun.uucp> Date: 1 Jun 88 06:10:03 GMT References: <14968@brl-adm.ARPA> <264@sdba.UUCP> Sender: news@sun.uucp Lines: 19 > Realizing that if this *is* true on the RoadRuner it will be > true at a much lower number, No, not true. The RR has about the same raw CPU speed as a 3/200-series machine. Furthermore, it has a different memory management unit; it appears the MMU may be the crux of the biscuit here. > does anyone know if such a thing is true on it ? If, as would be indicated by the number of processes at which the knee occurs, the knee is caused by running out of MMU contexts (the Sun-3 MMU has 7 contexts available for user processes, the Sun-4 has 15), I would tend not to expect the same phenomenon on an RR; the '386 has a fairly conventional in-memory-page-table MMU. DISCLAIMER: This is just an educated guess. I don't have any numbers to back this up. Don't take this as gospel truth; if you *do* get numbers, let us all know, the results may be interesting (especially if they *don't* back this guess up).