From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754836AbXKSVor (ORCPT ); Mon, 19 Nov 2007 16:44:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752596AbXKSVoj (ORCPT ); Mon, 19 Nov 2007 16:44:39 -0500 Received: from ozlabs.org ([203.10.76.45]:56451 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751996AbXKSVoi (ORCPT ); Mon, 19 Nov 2007 16:44:38 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18242.900.101842.261763@cargo.ozlabs.ibm.com> Date: Tue, 20 Nov 2007 08:43:32 +1100 From: Paul Mackerras To: David Miller Cc: hch@infradead.org, akpm@linux-foundation.org, gregkh@suse.de, mucci@cs.utk.edu, eranian@hpl.hp.com, wcohen@redhat.com, robert.richter@amd.com, linux-kernel@vger.kernel.org, andi@firstfloor.org Subject: Re: [perfmon] Re: [perfmon2] perfmon2 merge news In-Reply-To: <20071119.050843.48408777.davem@davemloft.net> References: <20071114.152134.266510129.davem@davemloft.net> <18235.40110.831730.847548@cargo.ozlabs.ibm.com> <20071114.172722.71465976.davem@davemloft.net> <20071119.050843.48408777.davem@davemloft.net> X-Mailer: VM 7.19 under Emacs 21.4.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org David Miller writes: > As a result I've found that perfmon2 is quite nice and allows > incredibly useful and powerful tools to be written. The syscalls > aren't that bad and really I see not reason to block it's inclusion. > > I rescind all of my earlier objections, let's merge this soon :-) Strongly agree. However, I think we need to add structure size arguments to most of the syscalls so we can extend them later. Also, something I've been meaning to mention to Stephane is that the use of the cast_ulp() macro in perfmon is bogus and won't work on 32-bit big-endian platforms such as ppc32 and sparc32. On such platforms you can't take a pointer to an array of u64, cast it to unsigned long * and expect the kernel bitmap operations to work correctly on it. At the least you also need to XOR the bit numbers with 32 on those platforms. Another alternative is to define the bitmaps as arrays of bytes instead, which eliminates all byte ordering and wordsize problems (but makes it more tricky to use the kernel bitmap functions directly). Paul.