From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752725AbdKTUV6 (ORCPT ); Mon, 20 Nov 2017 15:21:58 -0500 Received: from mail-it0-f53.google.com ([209.85.214.53]:45688 "EHLO mail-it0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752691AbdKTUV4 (ORCPT ); Mon, 20 Nov 2017 15:21:56 -0500 X-Google-Smtp-Source: AGs4zMZ/YwSFYuMyRWfkMGaXTIu6+jt1UNaPz+i/ThD3QpM3X2CEOsTQwsp5YOmLwFPE2pJVMzHyTA== Date: Mon, 20 Nov 2017 12:21:52 -0800 From: Sami Tolvanen To: Nicholas Piggin Cc: Alex Matveev , Andi Kleen , Ard Biesheuvel , Greg Hackmann , Kees Cook , linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, Mark Rutland , Masahiro Yamada , Maxim Kuvyrkov , Michal Marek , Nick Desaulniers , Yury Norov , Matthias Kaehlcke Subject: Re: [v2,12/18] kbuild: add support for clang LTO Message-ID: <20171120202152.GA89108@samitolvanen.mtv.corp.google.com> References: <20171115213428.22559-13-samitolvanen@google.com> <20171118132139.58ac5e4c@roar.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171118132139.58ac5e4c@roar.ozlabs.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 18, 2017 at 01:21:39PM +1000, Nicholas Piggin wrote: > Do you have any kind of numbers for this, out of curiosity? Binary > size, performance, build time? I don't have performance numbers to share. Are there any specific benchmarks you'd be interested in seeing? Build time typically increases with LTO and in my experience, binary size tends to increase by ~10-15% as well. > Why is this needed? It would have been nice to get rid of the > !THIN_ARCHIVES option if you can make the patches work with the thin > archives paths. I believe LLVMgold doesn't know how to deal with an archive of LLVM IR files, but I can certainly use thin archives as an index and extract the path names for linking. I'll look into it. Sami From mboxrd@z Thu Jan 1 00:00:00 1970 From: samitolvanen@google.com (Sami Tolvanen) Date: Mon, 20 Nov 2017 12:21:52 -0800 Subject: [v2,12/18] kbuild: add support for clang LTO In-Reply-To: <20171118132139.58ac5e4c@roar.ozlabs.ibm.com> References: <20171115213428.22559-13-samitolvanen@google.com> <20171118132139.58ac5e4c@roar.ozlabs.ibm.com> Message-ID: <20171120202152.GA89108@samitolvanen.mtv.corp.google.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sat, Nov 18, 2017 at 01:21:39PM +1000, Nicholas Piggin wrote: > Do you have any kind of numbers for this, out of curiosity? Binary > size, performance, build time? I don't have performance numbers to share. Are there any specific benchmarks you'd be interested in seeing? Build time typically increases with LTO and in my experience, binary size tends to increase by ~10-15% as well. > Why is this needed? It would have been nice to get rid of the > !THIN_ARCHIVES option if you can make the patches work with the thin > archives paths. I believe LLVMgold doesn't know how to deal with an archive of LLVM IR files, but I can certainly use thin archives as an index and extract the path names for linking. I'll look into it. Sami