Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752130Ab0ATJ6G (ORCPT ); Wed, 20 Jan 2010 04:58:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751634Ab0ATJ6F (ORCPT ); Wed, 20 Jan 2010 04:58:05 -0500 Received: from mailout4.w1.samsung.com ([210.118.77.14]:30068 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750877Ab0ATJ6A convert rfc822-to-8bit (ORCPT ); Wed, 20 Jan 2010 04:58:00 -0500 MIME-version: 1.0 Content-type: text/plain; charset=utf-8; format=flowed; delsp=yes Date: Wed, 20 Jan 2010 10:57:08 +0100 From: =?utf-8?B?TWljaGHFgiBOYXphcmV3aWN6?= Subject: Re: [PATCH/RFC v1 0/2] Human readable performance event description in sysfs In-reply-to: <1263978999.4283.823.camel@laptop> To: Peter Zijlstra , Tomasz Fujak Cc: jpihet@mvista.com, p.osciak@samsung.com, jamie.iles@picochip.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, kyungmin.park@samsung.com, mingo@elte.hu, linux-arm-kernel@lists.infradead.org, m.szyprowski@samsung.com Message-id: Organization: Samsung Electronics 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> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1772 Lines: 39 >> The following patches provide a sysfs entry with hardware event human >> readable description in the form of "0x%llx\t%lld-%lld\t%s\t%s" % >> (event_value, minval, maxval, name, description) and means to populate >> the file. >> >> The intended use is twofold: for users to read the list directly and >> for tools (like perf). On Wed, 20 Jan 2010 10:16:39 +0100, Peter Zijlstra wrote: > Why do this in kernel space? Listing available events seems like > something we can do from userspace just fine. IMO kernel knows better what hardware it's running on and user space should not care and if this list were to be kept in user space it would have to detect the processor it's running on and act accordingly. Also, keeping the list in user space could lead to different software maintaining separate lists which would get out of sync. I think it's easier to update a single list in kernel then wait till all the software packages update theirs. This also means that different tools would use different names and descriptions for the events which would only increase confusion. Moreover, since kernel already does the hard work of detecting CPU it may provide a list as well. But I'm just a humble coder, what do I know... ;) -- 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/