On Wed, Feb 14, 2018 at 6:44 PM, Kilian Cavalotti <kilian.cavalotti.w...@gmail.com> wrote: > On Wed, Feb 14, 2018 at 2:26 PM, David Mathog <mat...@caltech.edu> wrote: >> Checked the hugepage settings and found a difference there. The two systems >> that don't do this have /sys/kernel/mm/redhat_transparent_hugepage/defrag >> >> always madvise [never] >> >> whereas the system with the issue has: >> >> [always] madvise never > > THP defragmentation is definitely something that has bitten us in the > past, when under memory pressure, and we now default to [madvise] > pretty much everywhere (we're too timid to disable it entirely).
i will second this stance as well. i've seen huge issues with disk performance when hugepage was enabled. i disable it on all the machines we have now. the way i found it was when doing large IO with hugepages enabled, the khugepage (sp?) process shoots right to the top of a top display. and the performance you describe was the same. _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
