From: Anton Blanchard <anton@samba.org>
To: benh@kernel.crashing.org
Cc: linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 5/5] powerpc: Increase NR_IRQS Kconfig maximum to 32768
Date: Sun, 31 Jan 2010 22:14:03 +1100 [thread overview]
Message-ID: <20100131111403.GP2996@kryten> (raw)
In-Reply-To: <20100131111315.GO2996@kryten>
With dynamic irq descriptors the overhead of a large NR_IRQS is much lower
than it used to be. With more MSI-X capable adapters and drivers exploiting
multiple vectors we may as well allow the user to increase it beyond the
current maximum of 512.
32768 seems large enough that we'd never have to bump it again (although I bet
my prediction is horribly wrong). It boot tests OK and the vmlinux footprint
increase is only around 500kB due to:
struct irq_map_entry irq_map[NR_IRQS];
We format /proc/interrupts correctly with the previous changes:
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5
286: 0 0 0 0 0 0
516: 0 0 0 0 0 0
16689: 1833 0 0 0 0 0
17157: 0 0 0 0 0 0
17158: 319 0 0 0 0 0
25092: 0 0 0 0 0 0
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: linux-cpumask/arch/powerpc/Kconfig
===================================================================
--- linux-cpumask.orig/arch/powerpc/Kconfig 2010-01-31 15:07:11.707211107 +1100
+++ linux-cpumask/arch/powerpc/Kconfig 2010-01-31 21:52:39.999711689 +1100
@@ -58,7 +58,7 @@ config IRQ_PER_CPU
config NR_IRQS
int "Number of virtual interrupt numbers"
- range 32 512
+ range 32 32768
default "512"
help
This defines the number of virtual interrupt numbers the kernel
next prev parent reply other threads:[~2010-01-31 11:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-31 11:09 [PATCH 1/5] powerpc: Rework /proc/interrupts Anton Blanchard
2010-01-31 11:10 ` [PATCH 2/5] powerpc: Remove whitespace in irq chip name fields Anton Blanchard
2010-01-31 11:11 ` [PATCH 3/5] powerpc: Add timer, performance monitor and machine check counts to /proc/interrupts Anton Blanchard
2010-01-31 11:13 ` [PATCH 4/5] powerpc: Convert global "BAD" interrupt to per cpu spurious Anton Blanchard
2010-01-31 11:14 ` Anton Blanchard [this message]
2010-01-31 20:35 ` [PATCH 5/5] powerpc: Increase NR_IRQS Kconfig maximum to 32768 Benjamin Herrenschmidt
2010-02-01 9:09 ` Gabriel Paubert
2010-02-01 10:04 ` Benjamin Herrenschmidt
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