On Mon, Nov 23, 2015 at 9:30 AM, Kevin Grittner <kgri...@gmail.com> wrote: > On Mon, Nov 23, 2015 at 12:20 AM, 657985...@qq.com <657985...@qq.com> wrote: > >> [root@pg1 ~]# cat /sys/kernel/mm/transparent_hugepage/enabled >> [always] madvise never >> [root@pg1 ~]# cat /sys/kernel/mm/transparent_hugepage/defrag >> [always] madvise never > > There's your problem. You need to set those to "never". You can > get immediate relief by echoing 'never' to those pseudo-files, but > you need to configure your system to set them at OS boot time, too.
yup. IMNSHO automatic enabling of THP defrag is one of the worst performance related mistakes I've ever seen in the history of the linux kernel (although maybe the blame lies with the distros...I'm not sure). It caused a number of terrible outages here before we figured out the underlying cause. (of course, everyone blamed postgres until then) merlin -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
