Huge pages part 3: Administration [LWN.net]

Huge pages part 3: Administration

Posted Jun 21, 2011 13:20 UTC (Tue) by ingomueller.net (guest, #75817)
Parent article: Huge pages part 3: Administration

It took me some time to enalbe 1GB pages on my x86_64 machine. There are two essential steps I needed:

1) Make sure the processor supports 1GB pages. If the CPU supports 2MB pages, it has the PSE cpuinfo flag, for 1GB it has the PDPE1GB flag. /proc/cpuinfo shows whether the two flags are set.

% grep pdpe1gb /proc/cpuinfo | uniq
flags           : [...] pdpe1gb [...]

At this point, they are not yet activated:

% hugeadm --pool-list
      Size  Minimum  Current  Maximum  Default
   2097152        0        0        0        *

2) Enable the support at boot time. The following kernel boot parameters enable 1GB pages and create a pool of one 1GB page:

hugepagesz=1GB hugepages=1

Now, after booting with the above options, we have a 1GB page pool with one page:

% hugeadm --pool-list
      Size  Minimum  Current  Maximum  Default
   2097152        0        0        0        *
1073741824        1        1        1

See more for the kernel options here: http://www.fogproject.org/wiki/index.php?title=Kernel_Parameters

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