LWN.net Logo

little systems

little systems

Posted Jul 2, 2003 19:40 UTC (Wed) by jimi (guest, #6655)
In reply to: little systems by johnjones
Parent article: An interview with Linus Torvalds

Linus has stated previously that scalability goes both ways: large systems and small systems. Software that only scales up isn't very scalable, it must also scale down. So I think he and others are aware of trying to make things work well in very small systems (in fact, newer kernels often have increased performance on the same old hardware).

As for SMP, the locking improves constantly. But the best solution probably isn't to have a kernel running on each CPU. Interrupts from the same device aren't always received on the same CPU. Imagine trying to coordinate interrupt processing between seperate kernels. Fouther problems arise in memory management, particularly on non-NUMA systems (which kernel owns which memory? How do you keep one kernel from stomping on the memory of another? How do you allocate large chunks of memory for an app? Let the kernels fight it out? Does that mean that an app would be tied to one kernel?)


(Log in to post comments)

definition of scalability

Posted Jul 3, 2003 23:09 UTC (Thu) by giraffedata (subscriber, #1954) [Link]

>Software that only scales up isn't very scalable

The wording here actually weakens a very good point. There is no such thing as "only scales up." That's like saying a property line only runs East. Scalable means the size can be big or small. If you make Linux work great on a large system and not on a small system, it doesn't scale up. It's always up.

Copyright © 2013, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds