On Fri, Jun 29, 2012 at 1:00 PM, Merlin Moncure <mmonc...@gmail.com> wrote: > On Fri, Jun 29, 2012 at 2:52 PM, Andres Freund <and...@2ndquadrant.com> wrote: >> Hi All, >> >> In a *very* quick patch I tested using huge pages/MAP_HUGETLB for the mmap'ed >> memory. >> That gives around 9.5% performance benefit in a read-only pgbench run (-n -S >> - >> j 64 -c 64 -T 10 -M prepared, scale 200, 6GB s_b, 8 cores, 24GB mem). >> >> It also saves a bunch of memory per process due to the smaller page table >> (shared_buffers 6GB): >> cat /proc/$pid_of_pg_backend/status |grep VmPTE >> VmPTE: 6252 kB >> vs >> VmPTE: 60 kB > ... those results are just spectacular (IMO). nice!
That is super awesome. Smallish databases with a high number of connections actually spend a considerable fraction of their otherwise-available-for-buffer-cache space on page tables in common cases currently. -- fdr -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
