Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dFhtP-00012p-1T for pgsql-pkg-debian@arkaria.postgresql.org; Tue, 30 May 2017 14:13:03 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1dFhtO-0007hS-5W for pgsql-pkg-debian@arkaria.postgresql.org; Tue, 30 May 2017 14:13:02 +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 1dFhtN-0007hD-TZ; Tue, 30 May 2017 14:13:01 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1dFhtK-00013u-QB; Tue, 30 May 2017 14:13:01 +0000 Received: from sss1.sss.pgh.pa.us (localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.4/8.14.4) with ESMTP id v4UECkGr011630; Tue, 30 May 2017 10:12:46 -0400 From: Tom Lane To: Robert Haas cc: Christoph Berg , Andres Freund , Jason Petersen , pgsql-pkg-debian@postgresql.org, PostgreSQL Hackers Subject: Re: [HACKERS] [PATCH] relocation truncated to fit: citus build failure on s390x In-reply-to: References: <980D4281-A01F-4F5D-9874-FFED701F403F@citusdata.com> <20160426151339.GF12563@msg.df7cb.de> <20160426153235.GA2862@msg.df7cb.de> <20160427230516.44fuzdxlifch2wwp@alap3.anarazel.de> <20160428080824.GA22412@msg.df7cb.de> <20170529155850.qojdfrwkkqnjb3ap@msg.df7cb.de> <27883.1496087111@sss.pgh.pa.us> Comments: In-reply-to Robert Haas message dated "Tue, 30 May 2017 10:02:56 -0400" MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <11628.1496153566.1@sss.pgh.pa.us> Date: Tue, 30 May 2017 10:12:46 -0400 Message-ID: <11629.1496153566@sss.pgh.pa.us> X-Pg-Spam-Score: -1.9 (-) X-Mailing-List: pgsql-pkg-debian List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Precedence: bulk Sender: pgsql-pkg-debian-owner@postgresql.org Robert Haas writes: > On Mon, May 29, 2017 at 3:45 PM, Tom Lane wrote: >> I wonder what the overhead is of using -fPIC when -fpic would be >> sufficient. > Do we have an idea how to measure the increased overhead? Just from > reading the description, I'm guessing that the increased cost would > happen when the extension calls back into core, but maybe that doesn't > happen often enough to worry about? My gut feeling is that it'd be a pretty distributed cost, because every internal cross-reference in the .so (for instance, loading the address of a string literal) would involve a bit more overhead to support a wider offset field. An easy thing to look at would be how much the code expands by. That might or might not be a good proxy for the runtime slowdown percentage, but it seems like it ought to serve as a zero-order approximation. regards, tom lane -- Sent via pgsql-pkg-debian mailing list (pgsql-pkg-debian@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-pkg-debian