Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1aHGXX-0003Vw-4h for pgsql-performance@arkaria.postgresql.org; Thu, 07 Jan 2016 19:48:07 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84) (envelope-from ) id 1aHGXW-0003Lr-Lg for pgsql-performance@arkaria.postgresql.org; Thu, 07 Jan 2016 19:48:06 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84) (envelope-from ) id 1aHGXW-0003Ll-Al for pgsql-performance@postgresql.org; Thu, 07 Jan 2016 19:48:06 +0000 Received: from mail.anarazel.de ([217.115.131.40]) by magus.postgresql.org with esmtp (Exim 4.84) (envelope-from ) id 1aHGXT-0004Ex-1x for pgsql-performance@postgresql.org; Thu, 07 Jan 2016 19:48:05 +0000 Received: by mail.anarazel.de (Postfix, from userid 108) id 9A978860002; Thu, 7 Jan 2016 20:48:02 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on mail X-Spam-Level: X-Spam-Status: No, score=-5.6 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 Received: from anarazel.de (p57B4E922.dip0.t-ipconnect.de [87.180.233.34]) (Authenticated sender: andres@anarazel.de) by mail.anarazel.de (Postfix) with ESMTPSA id B5F57860001; Thu, 7 Jan 2016 20:47:59 +0100 (CET) Received: by anarazel.de (Postfix, from userid 1000) id 44FAF10C6A1; Thu, 7 Jan 2016 20:47:59 +0100 (CET) Date: Thu, 7 Jan 2016 20:47:59 +0100 From: Andres Freund To: Tom Lane Cc: Rick Otten , "pgsql-performance@postgresql.org" Subject: Re: Queries intermittently slow Message-ID: <20160107194759.GM7650@awork2.anarazel.de> References: <28587.1452097950@sss.pgh.pa.us> <568DE640.5070508@BlueTreble.com> <13261.1452179944@sss.pgh.pa.us> <9E456947-7273-4D62-A5A1-D66F24052A00@yahoo.com> <13016.1452191691@sss.pgh.pa.us> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <13016.1452191691@sss.pgh.pa.us> X-Pg-Spam-Score: -4.2 (----) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org On 2016-01-07 13:34:51 -0500, Tom Lane wrote: > It's fairly well established that the implementation of transparent > huge pages in Linux kernels from the 2.6-or-so era sucks, and you're > best off turning it off if you care about consistency of performance. I think the feature wasn't introduced in original 2.6 kernels (3.2 or so?), but red hat had backported it to their 2.6.32 kernel. > I am not sure whether modern kernels have improved this area. I think the problem has largely been solved around 3.16. Around 4.1 I could still reproduce problems, but the regressions were only in the sub 10% range in my test workload. Andres -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance