Re: [PATCH] pte prefetching

From: David Mosberger <>
Date: 2005-03-25 07:15:12
>>>>> On Thu, 24 Mar 2005 18:18:17 +1100, Nick Piggin <> said:

  Nick> After applying the recent freepgt patchset from Hugh (on
  Nick> lkml), the time to fork+exit a process mapping 64GB of address
  Nick> (32MB of page tables) is 0.471s. With the prefetch patch, this
  Nick> drops to 0.357s.

Looks like a nice improvement to me.

Does prefetching 1 line ahead give the best results?  That's only
128/8=16 PTEs.  Assuming a 200 cycle latency, this would allow
for only 12.5 cycles/iteration.  Especially for large (NUMA) machines,
prefetching further out might help more.


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Received on Thu Mar 24 15:16:27 2005

This archive was generated by hypermail 2.1.8 : 2005-08-02 09:20:37 EST