Jason R Thorpe wrote:

For an R4400 pmax, the only real difference with uvm_pageidlezero() is
a reduction in L2 cache latency - here's two runs before and two runs
after (in that order :-):

Memory latencies in nanoseconds - smaller is better
    (WARNING - may not be correct, check graphs)
---------------------------------------------------
Host                 OS   Mhz  L1 $   L2 $    Main mem    Guesses
--------- -------------   ---  ----   ----    --------    -------
pmax-netb   NetBSD 1.4X   118    25    263        1248
pmax-netb   NetBSD 1.4X   118    25    291        1251
pmax-netb   NetBSD 1.4X   118    25    126        1250
pmax-netb   NetBSD 1.4X   118    25    126        1251

mmap latency is still around 150-160ms...

Simon.