On Wed, Aug 20, 2014 at 12:13:50PM -0700, Josh Berkus wrote: > On a read-write test, it's 10% faster with HT off as well. > > Further, from their production machine we've seen that having HT on > causes the machine to slow down by 5X whenever you get more than 40 > cores (as in 100% of real cores or 50% of HT cores) worth of activity. > > So we're definitely back to "If you're using PostgreSQL, turn off > Hyperthreading". Not sure how you can make such a blanket statement when so many people have tested and shown the benefits of hyper-threading. I am also unclear exactly what you tested, as I didn't see it mentioned in the email --- CPU type, CPU count, and operating system would be the minimal information required. -- Bruce Momjian <bruce@xxxxxxxxxx> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
