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d="scan'208";a="292419767" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.21]) by orsmga006.jf.intel.com with ESMTP; 03 Aug 2020 21:45:32 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 40984301C06; Mon, 3 Aug 2020 21:45:32 -0700 (PDT) Date: Mon, 3 Aug 2020 21:45:32 -0700 From: Andi Kleen To: Arvind Sankar Subject: Re: [PATCH v5 13/36] vmlinux.lds.h: add PGO and AutoFDO input sections Message-ID: <20200804044532.GC1321588@tassilo.jf.intel.com> References: <20200731230820.1742553-1-keescook@chromium.org> <20200731230820.1742553-14-keescook@chromium.org> <20200801035128.GB2800311@rani.riverdale.lan> <20200803190506.GE1299820@tassilo.jf.intel.com> <20200803201525.GA1351390@rani.riverdale.lan> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200803201525.GA1351390@rani.riverdale.lan> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200804_004534_796744_8CCB24D1 X-CRM114-Status: GOOD ( 15.27 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , linux-efi@vger.kernel.org, Catalin Marinas , Manoj Gupta , Will Deacon , Thomas Gleixner , linux-arch@vger.kernel.org, =?utf-8?B?RsSBbmctcnXDrCBTw7JuZw==?= , Masahiro Yamada , x86@kernel.org, Russell King , Ard Biesheuvel , clang-built-linux@googlegroups.com, Ingo Molnar , Luis Lozano , Borislav Petkov , Kees Cook , Arnd Bergmann , Jian Cai , Nathan Chancellor , Peter Collingbourne , linux-arm-kernel@lists.infradead.org, Michal Marek , Nick Desaulniers , linux-kernel@vger.kernel.org, stable@vger.kernel.org, James Morse Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org > Why is that? Both .text and .text.hot have alignment of 2^4 (default > function alignment on x86) by default, so it doesn't seem like it should > matter for packing density. Avoiding interspersing cold text among You may lose part of a cache line on each unit boundary. Linux has a lot of units, some of them small. All these bytes add up. It's bad for TLB locality too. Sadly with all the fine grained protection changes the 2MB coverage is eroding anyways, but this makes it even worse. > regular/hot text seems like it should be a net win. > > That old commit doesn't reference efficiency -- it says there was some > problem with matching when they were separated out, but there were no > wildcard section names back then. It was about efficiency. -Andi _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel