Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752729Ab0ATOzQ (ORCPT ); Wed, 20 Jan 2010 09:55:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751735Ab0ATOzP (ORCPT ); Wed, 20 Jan 2010 09:55:15 -0500 Received: from mailout2.w1.samsung.com ([210.118.77.12]:42527 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751988Ab0ATOzO convert rfc822-to-8bit (ORCPT ); Wed, 20 Jan 2010 09:55:14 -0500 Date: Wed, 20 Jan 2010 15:54:22 +0100 From: =?utf-8?B?TWljaGHFgiBOYXphcmV3aWN6?= Subject: Re: [PATCH/RFC v1 0/2] Human readable performance event description in sysfs In-reply-to: <1263996979.4283.1066.camel@laptop> To: Peter Zijlstra Cc: Russell King - ARM Linux , jpihet@mvista.com, p.osciak@samsung.com, Jamie Iles , will.deacon@arm.com, linux-kernel@vger.kernel.org, kyungmin.park@samsung.com, mingo@elte.hu, Tomasz Fujak , linux-arm-kernel@lists.infradead.org, m.szyprowski@samsung.com Message-id: Organization: Samsung Electronics MIME-version: 1.0 Content-type: text/plain; charset=utf-8; format=flowed; delsp=yes Content-transfer-encoding: 8BIT User-Agent: Opera Mail/10.10 (Linux) References: <1263978706-15499-1-git-send-email-t.fujak@samsung.com> <1263978999.4283.823.camel@laptop> <20100120133145.GE4089@wear.picochip.com> <1263994779.4283.1057.camel@laptop> <20100120135553.GA22897@n2100.arm.linux.org.uk> <1263996080.4283.1064.camel@laptop> <1263996979.4283.1066.camel@laptop> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1958 Lines: 39 >> On Wed, 20 Jan 2010 15:01:20 +0100, Peter Zijlstra wrote: >>> It seems to me userspace might care about the exact platform they're >>> running on. > On Wed, 2010-01-20 at 15:09 +0100, Michał Nazarewicz wrote: >> In my humble opinion, user space should never care about platform it's >> running on. Interfaces provided by kernel should suffice to implement >> abstraction layer between user space and hardware. If we abandon that >> we're back in DOS times. But hey, again, that's just my opinion. On Wed, 20 Jan 2010 15:16:19 +0100, Peter Zijlstra wrote: > Well, you're completely right. But the often sad reality is that perfect > abstraction is either impossible or prohibitively expensive. Yes, I agree and am aware of that, but I think it's not the case with performance events. It is possible for kernel to provide such a list and at the same time it's not that expensive (it's a matter of hardcoding a list in the source and possibly alter it a bit according to hardware detection which is done anyway). Of course, it's not all gold -- maintaining such a list increases complexity of the kernel and adds burden of keeping the lists in sync with reality. Still, however, in my opinion, the advantages of the list maintained in kernel are greater then disadvantages and so I'd opt in for that solution. (Of course, I'm not some kind of ARM Linux guru so I may be simply wrong.) -- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał "mina86" Nazarewicz (o o) ooo +---[mina86@mina86.com]---[mina86@jabber.org]---ooO--(_)--Ooo-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/