From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753519AbZIXOmr (ORCPT ); Thu, 24 Sep 2009 10:42:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753481AbZIXOmp (ORCPT ); Thu, 24 Sep 2009 10:42:45 -0400 Received: from smtp.polymtl.ca ([132.207.4.11]:48091 "EHLO smtp.polymtl.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753492AbZIXOmo (ORCPT ); Thu, 24 Sep 2009 10:42:44 -0400 X-Greylist: delayed 2108 seconds by postgrey-1.27 at vger.kernel.org; Thu, 24 Sep 2009 10:42:44 EDT Message-Id: <20090924132626.485545323@polymtl.ca> User-Agent: quilt/0.46-1 Date: Thu, 24 Sep 2009 09:26:26 -0400 From: Mathieu Desnoyers To: Ingo Molnar , linux-kernel@vger.kernel.org Subject: [patch 00/12] Immediate Values X-Poly-FromMTA: (test.casi.polymtl.ca [132.207.72.60]) at Thu, 24 Sep 2009 14:07:31 +0000 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ingo, Here is an updated version of the immediate values, applying to current tip. [impact: data-cache optimization] The main benefit of this infrastructure is to encode read-often variables into the instruction stream. It can benefit to tracepoints by replacing the memory load by an immediate value instruction. There is still room for improvement through: an effort to provide static jump patching is ongoing, involving the kernel and gcc communities. Even then, the immediate values have their niche: when a value (rather than a branch selection) is read often on fast-paths, the immediate value infrastructure can encode these in the instruction stream without any d-cache cost. Two sample users are provided: prof_on from the scheduler code and tracepoints. Feel free to merge/drop any of these. Thanks, Mathieu -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68