re: mmap over nfs leads to excessive system load

[Trond Myklebust <trond.myklebust@fys.uio.no>]

On Tue, 2005-11-08 at 11:25 -0800, Kenny Simpson wrote:
> Just another data point....
> If I open the file with O_DIRECT.. not much changes:

Hmm... Are you mounting using the -osync or -onoac options? Doing
synchronous writes will tend to slow down flushing considerably, and the
VM appears to be very fragile w.r.t. slow filesystems.

Cheers,
  Trond


> samples  %        image name               app name                 symbol name
> 12585321 18.9373  vmlinux-2.6.14           vmlinux-2.6.14           find_get_pages_tag
> 8608887  12.9539  vmlinux-2.6.14           vmlinux-2.6.14           mpage_writepages
> 6870600  10.3383  vmlinux-2.6.14           vmlinux-2.6.14           unlock_page
> 6605417   9.9393  vmlinux-2.6.14           vmlinux-2.6.14           clear_page_dirty_for_io
> 6259207   9.4183  vmlinux-2.6.14           vmlinux-2.6.14           release_pages
> 3249493   4.8896  vmlinux-2.6.14           vmlinux-2.6.14           __lookup_tag
> 3248871   4.8886  vmlinux-2.6.14           vmlinux-2.6.14           pci_conf1_write
> 2677914   4.0295  vmlinux-2.6.14           vmlinux-2.6.14           page_waitqueue
> 982811    1.4789  vmlinux-2.6.14           vmlinux-2.6.14           _read_lock_irqsave
> 917165    1.3801  vmlinux-2.6.14           vmlinux-2.6.14           _read_unlock_irq
> 758960    1.1420  vmlinux-2.6.14           vmlinux-2.6.14           __wake_up_bit
> 706607    1.0632  vmlinux-2.6.14           vmlinux-2.6.14           _spin_lock_irqsave
> 
> 
> -Kenny
> 
> 
> 
> 	
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