Messages in this thread | | | Date | Sun, 2 Jul 2000 15:50:55 -0600 | From | yodaiken@fsmlabs ... | Subject | Re: a joint letter on low latency and Linux |
| |
On Sun, Jul 02, 2000 at 04:43:09PM -0400, Albert D. Cahalan wrote: > Digital UNIX (now Tru64, was OSF/1) uses self-modifying code to > create a generic kernel that can do, if I remember right: > > 1. plain > 2. real-time > 3. SMP > 4. real-time SMP > 5. lock debugging
I have a simple suggestion: When asserting that an OS has "real time" capabilities, include either the adjective "hard" and supply a time worst case interrupt latency on a representative hardware platform or include "soft" and supply a characterization of "typical" interrupt latencies and worst case number of violations.
> on a real i386 without being slow on a 486. Modules could work for > SMP, huge memory, and normal kernels. Exact process accounting could > be part of every kernel, but NOPed out at runtime if not enabled. > Perhaps even RT-Linux could use this ability.
Nops cost too but RTLinux V3 in the x86 does do some on-line code patching for Linux so that we can keep the Linux mods simple and pay a time cost only when we move into RT mode.
-- --------------------------------------------------------- Victor Yodaiken FSMLabs: www.fsmlabs.com www.rtlinux.com FSMLabs is a servicemark and a service of VJY Associates L.L.C, New Mexico.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |