On 5/10/12 12:37 PM, Alan Cox wrote:
On Thu, May 10, 2012 at 10:52 AM, Charles Owens
<cow...@greatbaysoftware.com <mailto:cow...@greatbaysoftware.com>> wrote:
That's very helpful! I had read about that and wondered if it
applied to i386.
Should I have expected "superpages" to completely cure the
condition... or does it just help? Should I now be looking at
tuning the related pmap sysctls to give further relief?
Superpages won't cure the problem due to the nature of your workload.
After a fork, writes to portions of the address space that are both
superpages and copy-on-write will trigger demotion, or
re-instantiation of the 4KB page granularity PV entries. Ultimately,
repromotion to superpages may occur, but in the meantime, your peak
usage of PV entries is only slightly reduced.
The bottom line is that you'll need to resort to tuning.
Alan
Ok. Very good.
Lastly, since we're talking about this (for the future) -- is enabling
of superpages generally recommended for amd64?
Thanks,
Charles
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