From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31104 invoked by alias); 9 Jun 2013 10:05:54 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 31046 invoked by uid 48); 9 Jun 2013 10:05:42 -0000 From: "jakub at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/57571] linux kernel function memcpy() execute with low efficiency on Intel Ivybridge platform Date: Sun, 09 Jun 2013 10:05:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 4.7.2 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: jakub at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2013-06/txt/msg00438.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57571 --- Comment #6 from Jakub Jelinek --- Anyway, please see http://gcc.gnu.org/bugs.html, without preprocessed source and gcc options passed to it this report is useless. Also, if it is a memcpy into a hardware device area, perhaps the kernel shouldn't use memcpy for that but some routine optimized for device memory access, the compiler isn't told in any way that it isn't normal memory and all it can do is choose best memcpy strategy for host memory to memory copies.