John Hawkes b60c1f6ffd [PATCH] drop note_interrupt() for per-CPU for proper scaling ... The "unhandled interrupts" catcher, note_interrupt(), increments a global desc->irq_count and grossly damages scaling of very large systems, e.g., >192p ia64 Altix, because of this highly contented cacheline, especially for timer interrupts. 384p is severely crippled, and 512p is unuseable. All calls to note_interrupt() can be disabled by booting with "noirqdebug", but this disables the useful interrupt checking for all interrupts. I propose eliminating note_interrupt() for all per-CPU interrupts. This was the behavior of linux-2.6.10 and earlier, but in 2.6.11 a code restructuring added a call to note_interrupt() for per-CPU interrupts. Besides, note_interrupt() is a bit racy for concurrent CPU calls anyway, as the desc->irq_count++ increment isn't atomic (which, if done, would make scaling even worse). Signed-off-by: John Hawkes <hawkes@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>		2005-05-28 11:14:00 -07:00
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irq	[PATCH] drop note_interrupt() for per-CPU for proper scaling	2005-05-28 11:14:00 -07:00
power
acct.c
audit.c
auditsc.c
capability.c
compat.c
configs.c
cpu.c
cpuset.c
dma.c
exec_domain.c
exit.c
extable.c
fork.c
futex.c
intermodule.c
itimer.c
kallsyms.c
kfifo.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
Makefile
module.c
panic.c
params.c
pid.c
posix-cpu-timers.c
posix-timers.c
printk.c
profile.c
ptrace.c
rcupdate.c
resource.c
sched.c
seccomp.c
signal.c
softirq.c
spinlock.c
stop_machine.c
sys_ni.c
sys.c
sysctl.c
time.c
timer.c
uid16.c
user.c
wait.c
workqueue.c