On Thu, Jun 05, 2003 at 02:12:32AM +0200, Ralf Baechle wrote: > On Wed, Jun 04, 2003 at 04:46:52PM -0700, Jun Sun wrote: > > > Assuming SGI systems represent the past of MIPS, we are still ok > > future-wise. :) > > You loose. The reasons why SGI did construct their systems that way are > still valid. It can be quite tricky to distribute the clock in large > systems - even for a moderate definition of large. And for ccNUMAs which > are going to show up on the embedded market sooner or later it's easy > for the lazy designer to use several clock sources anyway. Note our > current time code for will not work properly if clocks diverge on the > slightest bit - among other things the standards mandate time to > monotonically increase. > Aside from aficionado of SGI legacy, do you see any value in implementing this just for the applicable SMP systems? Here is my take: To implement an efficient and correct time management in SMP is a hard problem. I don't think there is a generic solution here. (Convince me if I am wrong.) Therefore for a set of "conforming" SMP systems which don't have the listed 3 issues, we provide a feasible solution. I don't see how we can avoid this - unless we don't care about getting time right. Jun
