1. 30 Dec, 2009 1 commit
    • Yinghai Lu's avatar
      x86: Increase NR_IRQS and nr_irqs · 9959c888
      Yinghai Lu authored
      I have a system with lots of igb and ixgbe, when iov/vf are
      enabled for them, we hit the limit of 3064.
      
      when system has 20 pcie installed, and one card has 2
      functions, and one function needs 64 msi-x,
       may need 20 * 2 * 64 = 2560 for msi-x
      
      but if iov and vf are enabled
       may need 20 * 2 * 64 * 3 = 7680 for msi-x
      assume system with 5 ioapic, nr_irqs_gsi will be 120.
      
      NR_CPUS = 512, and nr_cpu_ids = 128
      will have NR_IRQS = 256 + 512 * 64 = 33024
      will have nr_irqs = 120 + 8 * 128 + 120 * 64 = 8824
      
      When SPARSE_IRQ is not set, there is no increase with kernel data
      size.
      
      when NR_CPUS=128, and SPARSE_IRQ is set:
         text		   data	    bss		   dec		 hex	filename
      21837444	4216564	12480736	38534744	24bfe58	vmlinux.before
      21837442	4216580	12480736	38534758	24bfe66	vmlinux.after
      when NR_CPUS=4096, and SPARSE_IRQ is set
         text		   data	    bss		   dec		 hex	filename
      21878619	5610244	13415392	40904255	270263f	vmlinux.before
      21878617	5610244	13415392	40904253	270263d	vmlinux.after
      Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      LKML-Reference: <4B398ECD.1080506@kernel.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      9959c888
  2. 24 Dec, 2009 39 commits