I should also point out that the real-time scheduler primarily changes
the responsiveness of processes and threads that are scheduled with
real-time priorities.  Non-realtime threads are handled by the standard
scheduler algorithm, so if there's a bug in there it may very well
still be present with the real-time scheduler, unless it was something
we caught in our testing.

On Wed, 24 May 2000, diekema_jon wrote:

Previous message:

http://lists.linuxppc.org/listarcs/linuxppc-embedded/200005/msg00180.html

quoted

bad magic 0 (should be c01fb2e0, creator 0), wq bug, forcing oops.
kernel BUG at sched.c:656!
NIP: C000FB5C XER: 00000000 LR: C000FB5C REGS: c01adc00 TRAP: 0700
MSR: 00081032 EE: 0 PR: 0 FP: 0 ME: 1 IR/DR: 11
TASK = c01ac000[1] 'init' Last syscall: 6
last math 00000000 last altivec 00000000
GPR00: C000FB5C C01ADCB0 C01AC000 0000001B 00001032 C010EF80 C01FB260 C0128502
GPR08: 0000001B C0110000 F00000B8 C01ADBF0 24444028 1001EEB4 00000000 00000000
GPR16: 00000000 00000000 00000000 00000000 00009032 C01DA060 00000000 00000000
GPR24: 00000021 00000001 C01DA060 C010A3E0 C0125000 C0110000 C01FB2D4 C01ADCB0
Call backtrace:
C000FB5C C008CB8C C007F560 C007FE8C C0033CE4 C0033D80 C0032818
C00328CC C00328FC C00048F0 10005548 10005A20 0FF09E78 00000000
Kernel panic: Exception in kernel pc c000fb5c signal 4
Rebooting in 180 seconds..

We are walking into a scheduling bug in kernel/sched.c with Linux
2.3.99-pre9.  MontaVista has an experimental real-time scheduler that
can be installed into Linux 2.2.14.  Will this scheduler work with
Linux 2.3.99-pre9?  If it has a shot at working, I would like to try
it.  Perhaps I can avoid my problem.


From hhl-kernel-rtsched.patch:

REAL TIME SCHEDULER for Linux version 2.2.14

Released under the GNU Public License.

This patch contains the real time scheduler developed by
MontaVista Software, Inc.  It applies cleanly against the
Linux kernel version 2.2.14.  It adds the kernel configuration
option CONFIG_RTSCHED.  If CONFIG_RTSCHED=y, the real time
scheduler is configured, otherwise the standard scheduler is
used.

This patch also contains some fixes for the standard scheduler.

May 5, 2000:
Add real time scheduler option, as well as fixes for the standard scheduler.
This updated version fixes a build problem on the PowerPC.

CONTACT: [off-list ref]

--
Joe Green [off-list ref]
MontaVista Software, Inc.
(408) 328-9209

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/