From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755065Ab0FHSpL (ORCPT ); Tue, 8 Jun 2010 14:45:11 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:55488 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753450Ab0FHSpI (ORCPT ); Tue, 8 Jun 2010 14:45:08 -0400 Date: Tue, 8 Jun 2010 20:43:54 +0200 From: Ingo Molnar To: Lin Ming , Steven Rostedt Cc: Peter Zijlstra , Greg KH , Corey Ashford , Frederic Weisbecker , Paul Mundt , "eranian@gmail.com" , "Gary.Mohr@Bull.com" , "arjan@linux.intel.com" , "Zhang, Yanmin" , Paul Mackerras , "David S. Miller" , Russell King , Arnaldo Carvalho de Melo , Will Deacon , Maynard Johnson , Carl Love , Kay Sievers , lkml , Thomas Gleixner Subject: Re: [rfc] Describe events in a structured way via sysfs Message-ID: <20100608184354.GO11585@elte.hu> References: <1274236496.3603.22.camel@minggr.sh.intel.com> <20100519024823.GA25229@kroah.com> <1274253276.5605.10124.camel@twins> <20100520184213.GB21030@kroah.com> <20100520201418.GB11470@elte.hu> <20100520231229.GB8335@kroah.com> <1274429038.1674.1684.camel@laptop> <20100521094053.GA4658@elte.hu> <1275359672.7586.85.camel@minggr.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1275359672.7586.85.camel@minggr.sh.intel.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -1.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.0 required=5.9 tests=BAYES_20 autolearn=no SpamAssassin version=3.2.5 -1.0 BAYES_20 BODY: Bayesian spam probability is 5 to 20% [score: 0.1269] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Lin Ming wrote: > > > * Peter Zijlstra wrote: > > > > > On Thu, 2010-05-20 at 16:12 -0700, Greg KH wrote: > > > > > > How deep in the device tree are you really going to be > > > > caring about? It sounds like the large majority of > > > > events are only going to be coming from the "system" > > > > type objects (cpu, nodes, memory, etc.) and very few > > > > would be from things that we consider a 'struct > > > > device' today (like a pci, usb, scsi, or input, etc.) > > > > > > The general noise I hear from the hardware people is > > > that we'll see more and more device-level stuff - bus > > > bridges/controller and actual devices (GPUs, NICs etc.) > > > will be wanting to export performance metrics. > > > > There's (much) more: > > > > - laptops want to provide power level/usage metrics, > > > > - we could express a lot of special, lower level > > (transport specific) disk IO stats via events as well - > > without having to push those stats to a higher level > > (where it might not make sense). Currently such kinds > > of stats/metrics are very device/subsystem specific > > way, if they are provided at all. > > > > Also, we already have quite a few per device tracepoints > > upstream. Here are a few examples: > > > > - GPU tracepoints (trace_i915_gem_request_submit(), etc.) > > - WIFI tracepoints (trace_iwlwifi_dev_ioread32(), etc.) > > - block tracepoints (trace_block_bio_complete()) > > > > So these would be attached to: > > > > # GEM events of drm/card0: > > /sys/devices/pci0000:00/0000:00:02.0/drm/card0/events/i915_gem_request_submit/ > > > > # Wifi-ioread events of wlan0: > > /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlan0/events/iwlwifi_dev_ioread32/ > > > > # whole sdb disk events: > > /sys/block/sdb/events/block_bio_complete/ > > > > # sdb1 partition events: > > /sys/block/sdb/sdb1/events/block_bio_complete/ > > > > The difficulty is how to know where each event should be attached to. > > struct ftrace_event_call *call; > > for_each_event(call, __start_ftrace_events, __stop_ftrace_events) { > /* where will this event be attached to? */ > } > > Any idea? Well, it cannot be automatic - for each subsystem it's a different sysfs point. So it has to be specified in the TRACE_EVENT() definition or so. Ingo