On Wed, Sep 18, 2013 at 2:02 AM, Kevin Grittner <kgrittn@xxxxxxxxx> wrote: > Lonni J Friedman <netllama@xxxxxxxxx> wrote: > >> top shows over 90% of the load is in sys space. vmstat output >> seems to suggest that its CPU bound (or bouncing back & forth): > > Can you run `perf top` during an episode and see what kernel > functions are using all that CPU? Oddly, the problem went away on its own yesterday just after 4PM, and performance has remained 'normal' since that time. I changed absolutely nothing. If/when it returns, I'll certainly capture that output. > > This looks similar to cases I've seen of THP defrag going wild. > Did the OS version or configuration change? Did the PostgreSQL > memory settings (like shared_buffers) change? Nothing changed other than the version of postgres. I re-used the same postgresql.conf that was in place when running 9.2.x. Anyway, here are the current THP related settings on the server: [root@cuda-db7 ~]# grep AnonHugePages /proc/meminfo AnonHugePages: 548864 kB [root@cuda-db7 ~]# egrep 'trans|thp' /proc/vmstat nr_anon_transparent_hugepages 272 thp_fault_alloc 129173889 thp_fault_fallback 17462551 thp_collapse_alloc 148437 thp_collapse_alloc_failed 15143 thp_split 242 -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
