From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH v5 13/36] vmlinux.lds.h: add PGO and AutoFDO input sections Date: Mon, 3 Aug 2020 12:05:06 -0700 Message-ID: <20200803190506.GE1299820@tassilo.jf.intel.com> References: <20200731230820.1742553-1-keescook@chromium.org> <20200731230820.1742553-14-keescook@chromium.org> <20200801035128.GB2800311@rani.riverdale.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga14.intel.com ([192.55.52.115]:47829 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726130AbgHCTFR (ORCPT ); Mon, 3 Aug 2020 15:05:17 -0400 Content-Disposition: inline In-Reply-To: <20200801035128.GB2800311@rani.riverdale.lan> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arvind Sankar Cc: Kees Cook , Thomas Gleixner , Will Deacon , Nick Desaulniers , Jian Cai , =?utf-8?B?RsSBbmctcnXDrCBTw7JuZw==?= , Luis Lozano , Manoj Gupta , stable@vger.kernel.org, Catalin Marinas , Mark Rutland , Ard Biesheuvel , Peter Collingbourne , James Morse , Borislav Petkov , Ingo Molnar , Russell King , Masahiro Yamada , Nathan Chancellor , Arnd Bergmann , x86@kernel.org > However, the history of their being together comes from > > 9bebe9e5b0f3 ("kbuild: Fix .text.unlikely placement") > > which seems to indicate there was some problem with having them separated out, > although I don't quite understand what the issue was from the commit message. Separating it out is less efficient. Gives worse packing for the hot part if they are not aligned to 64byte boundaries, which they are usually not. It also improves packing of the cold part, but that probably doesn't matter. -Andi From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com ([192.55.52.115]:47829 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726130AbgHCTFR (ORCPT ); Mon, 3 Aug 2020 15:05:17 -0400 Date: Mon, 3 Aug 2020 12:05:06 -0700 From: Andi Kleen Subject: Re: [PATCH v5 13/36] vmlinux.lds.h: add PGO and AutoFDO input sections Message-ID: <20200803190506.GE1299820@tassilo.jf.intel.com> References: <20200731230820.1742553-1-keescook@chromium.org> <20200731230820.1742553-14-keescook@chromium.org> <20200801035128.GB2800311@rani.riverdale.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200801035128.GB2800311@rani.riverdale.lan> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arvind Sankar Cc: Kees Cook , Thomas Gleixner , Will Deacon , Nick Desaulniers , Jian Cai , =?utf-8?B?RsSBbmctcnXDrCBTw7JuZw==?= , Luis Lozano , Manoj Gupta , stable@vger.kernel.org, Catalin Marinas , Mark Rutland , Ard Biesheuvel , Peter Collingbourne , James Morse , Borislav Petkov , Ingo Molnar , Russell King , Masahiro Yamada , Nathan Chancellor , Arnd Bergmann , x86@kernel.org, clang-built-linux@googlegroups.com, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Michal Marek Message-ID: <20200803190506.vYuFXy3RWfROPlh6UqnFXO4ICDDG2R6Q7Mp7HVd0Dg8@z> > However, the history of their being together comes from > > 9bebe9e5b0f3 ("kbuild: Fix .text.unlikely placement") > > which seems to indicate there was some problem with having them separated out, > although I don't quite understand what the issue was from the commit message. Separating it out is less efficient. Gives worse packing for the hot part if they are not aligned to 64byte boundaries, which they are usually not. It also improves packing of the cold part, but that probably doesn't matter. -Andi