Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dlGmQ-00035b-5z for pgsql-performance@arkaria.postgresql.org; Fri, 25 Aug 2017 15:44:18 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1dlGmP-0006pw-OU for pgsql-performance@arkaria.postgresql.org; Fri, 25 Aug 2017 15:44:17 +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_2) (envelope-from ) id 1dlGmO-0006lp-A3 for pgsql-performance@postgresql.org; Fri, 25 Aug 2017 15:44:16 +0000 Received: from mail-it0-x232.google.com ([2607:f8b0:4001:c0b::232]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.84_2) (envelope-from ) id 1dlGmL-0007Ee-AU for pgsql-performance@postgresql.org; Fri, 25 Aug 2017 15:44:15 +0000 Received: by mail-it0-x232.google.com with SMTP id 77so980495itj.0 for ; Fri, 25 Aug 2017 08:44:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bowt-ie.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=MtICVb45MsJnt/aKZy6Xz8XJFmV8ZmzeJYqPmlQiK6E=; b=JFQ+oVjNkKfKn83fs8952dh1oK/Es1wCshY4R2nSqcIVtJnH7TVx7pRHrrp/0vCfi5 /TXsRvY7O6CNSqCJUj3+S0IgxWJGKyggWMKZVLixCnAQIabhLTqQplxk0fJUkqqlxPpx pNL3mG7fIry0DVCye1fpfWbhOPqP8StkDPpuEHWNdbz+mYu/e5uhUvBB1PyGRDLgzM1o 9U5BUnP5Dbup+AYyj9NRQZCIJ2APjg4wsz/GhzUkOSthWUYEzMa3JA/oABuPhGheVgyJ dCNe4GQamwLmQQfwM2eKuEP2SaMxMnOw55aH7kGtfQrN/Cm0Ghlc8dAwxaQF07UPDnih fgWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=MtICVb45MsJnt/aKZy6Xz8XJFmV8ZmzeJYqPmlQiK6E=; b=J/hewH29I8Ops5r0ndtbLq0gsjbOn+1e370pUmcIg6U+jN34NUyvaTxPfs7DtI2Xo5 0XABsIDxIsaDhzyOi9mXB+/kZlkuatyHUtt9M9ziL6Mgh1tCpA8jIy8mtWGtgVj2AnQm vfEet8ga4tZ4V57N1ZWgzX1L5ZT5kAJMkzu762nVtX3Kg7bITg4j3wX6fErGfj4r7suL eW49Ue/cGcXiXE0DHKjPtPCwdMJE01eNU+apvisBLA5aunN62e1x+86bnqoVBRzPiWzb QO/udbtg6I+tnT1r/8GBmzoeu2cXzVaaospPVMq9EimaSPW9HcUH3XN8V0xXDcfUPSbR wkFA== X-Gm-Message-State: AHYfb5hae/wiTgmKpfIkrsCFFpEENHhs6xsL56yb+an+MsZo5VTbqBrz 1x1ZXrvDgpx+5/ZTih7q/xr5546S4eW6jt4= X-Received: by 10.36.71.66 with SMTP id t63mr2535254itb.82.1503675850196; Fri, 25 Aug 2017 08:44:10 -0700 (PDT) MIME-Version: 1.0 Received: by 10.2.80.196 with HTTP; Fri, 25 Aug 2017 08:43:49 -0700 (PDT) In-Reply-To: <793.1503673641@sss.pgh.pa.us> References: <79C36278-87E4-4F9C-9C34-FA4ECB2B4B49@felixge.de> <793.1503673641@sss.pgh.pa.us> From: Peter Geoghegan Date: Fri, 25 Aug 2017 08:43:49 -0700 Message-ID: Subject: Re: 10x faster sort performance on Skylake CPU vs Ivy Bridge To: Tom Lane Cc: =?UTF-8?Q?Felix_Geisend=C3=B6rfer?= , postgres performance list Content-Type: text/plain; charset="UTF-8" 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 Fri, Aug 25, 2017 at 8:07 AM, Tom Lane wrote: > I doubt this is a hardware issue, it's more likely that you're comparing > apples and oranges. The first theory that springs to mind is that the > sort keys are strings and you're using C locale on the faster machine but > some non-C locale on the slower. strcoll() is pretty darn expensive > compared to strcmp() :-( strcoll() is very noticeably slower on macOS, too. -- Peter Geoghegan -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance