Commit Graph

3 Commits

Author SHA1 Message Date
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
Zhang, Yanmin
4f167fb491 [PATCH] spurious interrupt fix
On my IA64 machine, after kernel 2.6.12-rc3 boots, an edge-triggered
interrupt (IRQ 46) keeps triggered over and over again.  There is no IRQ 46
interrupt action handler.  It has lots of impact on performance.

Kernel 2.6.10 and its prior versions have no the problem.  Basically,
kernel 2.6.10 will mask the spurious edge interrupt if the interrupt is
triggered for the second time and its status includes
IRQ_DISABLE|IRQ_PENDING.

Originally, IA64 kernel has its own specific _irq_desc definitions in file
arch/ia64/kernel/irq.c.  The definition initiates _irq_desc[irq].status to
IRQ_DISABLE.  Since kernel 2.6.11, it was moved to architecture independent
codes, i.e.  kernel/irq/handle.c, but kernel/irq/handle.c initiates
_irq_desc[irq].status to 0 instead of IRQ_DISABLE.

Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-17 07:59:18 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00