summaryrefslogtreecommitdiffstats
path: root/kernel/irq/handle.c
diff options
context:
space:
mode:
authorRavikiran G Thirumalai <kiran@scalex86.org>2007-05-08 00:29:13 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:09 -0700
commite729aa16b168fb202d1a20f936028cb7c2a0278d (patch)
treed0267225ebfadbaa4f55f55c3025597d86ff1c5f /kernel/irq/handle.c
parent428e6ce023c5890cfecc8ad10335da3f28dbf893 (diff)
downloadop-kernel-dev-e729aa16b168fb202d1a20f936028cb7c2a0278d.zip
op-kernel-dev-e729aa16b168fb202d1a20f936028cb7c2a0278d.tar.gz
Pad irq_desc to internode cacheline size
We noticed a drop in n/w performance due to the irq_desc being cacheline aligned rather than internode aligned. We see 50% of expected performance when two e1000 nics local to two different nodes have consecutive irq descriptors allocated, due to false sharing. Note that this patch does away with cacheline padding for the UP case, as it does not seem useful for UP configurations. Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Shai Fultheim <shai@scalex86.org> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/irq/handle.c')
-rw-r--r--kernel/irq/handle.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index aff1f0f..515ad40 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -48,7 +48,7 @@ handle_bad_irq(unsigned int irq, struct irq_desc *desc)
*
* Controller mappings for all interrupt sources:
*/
-struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned = {
+struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
[0 ... NR_IRQS-1] = {
.status = IRQ_DISABLED,
.chip = &no_irq_chip,
OpenPOWER on IntegriCloud