From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [patch 00/11] convert slotslock to SRCU
Date: Sun, 27 Dec 2009 15:16:00 +0200
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References: <20091223113833.742662117@redhat.com>
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To: Marcelo Tosatti <mtosatti@redhat.com>
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On 12/23/2009 01:38 PM, Marcelo Tosatti wrote:
> Now that synchronize_srcu_expedited is in the tree, we can continue the
> convertion of slots_lock to SRCU.
>
> Results:
> up:
>
>    

Without this patchset, -smp 64 is simply unusable.  An _idle_ Linux 
guest generates enough interrupts that the system is unable to make any 
progress:


[root@monster01 ~]# perf report -g
# Samples: 14214748264314
#
# Overhead          Command                      Shared Object  Symbol
# ........  ...............  .................................  ......
#
     40.81%  qemu-system-x86  [kernel]                           [k] 
_raw_spin_lock_irq
             |
             --- _raw_spin_lock_irq
                |
                |--99.94%-- __down_read
                |          down_read
                |          |
                |          |--99.82%-- 0xffffffffa00479c4
                |          |          0xffffffffa003a6c9
                |          |          vfs_ioctl
                |          |          do_vfs_ioctl
                |          |          sys_ioctl
                |          |          system_call
                |          |          __GI_ioctl
                |           --0.18%-- [...]
                 --0.06%-- [...]

     40.57%  qemu-system-x86  [kernel]                           [k] 
_raw_spin_lock_irqsave
             |
             --- _raw_spin_lock_irqsave
                |
                |--99.88%-- __up_read
                |          up_read
                |          |
                |          |--99.82%-- 0xffffffffa0047897
                |          |          0xffffffffa003a6c9
                |          |          vfs_ioctl
                |          |          do_vfs_ioctl
                |          |          sys_ioctl
                |          |          system_call
                |          |          __GI_ioctl
                |           --0.18%-- [...]
                 --0.12%-- [...]

With this patchset, -smp 64 flies.  Patch to follow.  Amazing work!

(and surprising how easy it is to saturate a large system)

-- 
error compiling committee.c: too many arguments to function