From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757516Ab0FUI5P (ORCPT ); Mon, 21 Jun 2010 04:57:15 -0400 Received: from mga01.intel.com ([192.55.52.88]:60546 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753660Ab0FUI5H (ORCPT ); Mon, 21 Jun 2010 04:57:07 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,452,1272870000"; d="scan'208";a="578264921" Subject: Re: [rfc] Describe events in a structured way via sysfs From: Lin Ming To: Ingo Molnar 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 In-Reply-To: References: <1274233602.3036.84.camel@localhost> <20100518200524.GA20223@kroah.com> <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> Content-Type: text/plain Date: Mon, 21 Jun 2010 16:55:09 +0800 Message-Id: <1277110509.18390.28.camel@minggr.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > From: Ingo Molnar > > * 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/ > > And we also have 'software nodes' in /sys that have events > upstream here and today. For example for SLAB we already > have kmalloc/kfree tracepoints (trace_kmalloc() and > trace_kfree()): > > # all kmalloc events: > /sys/kernel/slab/events/ > > # kmalloc events for sighand_cache: > /sys/kernel/slab/sighand_cache/events/kmalloc/ > > # kfree events for sighand_cache: > /sys/kernel/slab/sighand_cache/events/kfree/ > > In general the set of events we have upstream is growing > along an exponential curve (there's over a hundred now, > via tracepoints). > > They are either logically attached to the hardware > topology of the system (as in the first set of examples > above), or ae attached to the software/subsystem object > topology of the kernel (some examples of which are > described in the second set of examples above). > > Sometimes there are aliasing/filtering relationship > between events, which is expressed very well via the > hierarchy and granularity of /sysfs. > > New events would go into that topology there in a natural > way. > > For example general hugepage tracepoints (should we > introduce any) would go into the existing hugepage node: > > /sys/kernel/mm/hugepages/events/... > > All in one, all these existing and future events, both of > hardware and software type, are literally begging to be > attached to nodes in /sys :-) (sorry for late response...) There are so many events via tracepoints, how about below sysfs point for each events? 1. kvm events /sys/devices/system/kvm/kvm0/events/kvm_set_irq/ ... /sys/devices/system/kvm/kvm0/events/kvm_emulate_insn/ 2. kvm_mmu events /sys/devices/system/kvm/kvm0/events/kvm_mmu_pagetable_walk/ ... /sys/devices/system/kvm/kvm0/events/kvm_mmu_zap_page/ 3. raw_syscalls events /sys/kernel/events/sys_enter/ /sys/kernel/events/sys_exit/ 4. mce events /sys/devices/system/machinecheck/machinecheck0/mce_record/ ... /sys/devices/system/machinecheck/machinecheckN/mce_record/ 5. sched events /sys/kernel/events/sched_kthread_stop/ ... /sys/kernel/events/sched_stat_runtime/ 6. irq events /sys/kernel/events/irq_handler_entry/ ... /sys/kernel/events/softirq_exit/ 7. timer events /sys/kernel/events/timer_init/ ... /sys/kernel/events/itimer_expire/ 8. signal events /sys/kernel/events/signal_generate/ ... /sys/kernel/events/signal_lose_info/ 9. workqueue events /sys/kernel/events/workqueue_insertion/ ... /sys/kernel/events/workqueue_destruction/ 10. lock events /sys/kernel/events/lock_acquire/ ... /sys/kernel/events/lock_acquired/ 11. module events /sys/module/events/module_load/ ... /sys/module/events/module_request/ 12. power events /sys/power/events/power_start/ ... /sys/power/events/power_end/ 13. kmem events /sys/kernel/mm/events/kmalloc/ ... /sys/kernel/mm/events/mm_page_alloc_extfrag/ 14. ext4 events /sys/fs/events/ext4_free_inode/ ... /sys/fs/events/ext4_mb_buddy_bitmap_load/ 15. jbd2 events /sys/fs/events/jbd2_checkpoint/ ... /sys/fs/events/jbd2_cleanup_journal_tail/ 16. xfs events /sys/fs/events/xfs_attr_list_sf/ ... /sys/fs/events/xfs_log_recover_inode_skip/ 17. gfs2 events /sys/fs/events/gfs2_glock_state_change/ ... /sys/fs/events/gfs2_block_alloc/ 18. block events /sys/block/sda/events/block_rq_abort/ ... /sys/block/sdb/events/block_rq_remap/ 19. bkl events /sys/kernel/events/lock_kernel/ ... /sys/kernel/events/unlock_kernel/ 20. scsi events /sys/bus/scsi/devices/0:0:0:0/events/scsi_dispatch_cmd_start/ ... /sys/bus/scsi/devices/0:0:0:0/events/scsi_eh_wakeup/ 21. iwlwifi_io events /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlan0/events/iwlwifi_dev_ioread32/ ... /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlan0/events/iwlwifi_dev_ucode_event/ 22. iwm events 23. skb events /sys/class/net/events/kfree_skb/ /sys/class/net/events/skb_copy_datagram_iovec/ 24. napi events /sys/class/net/events/napi/ 25. mac80211 events /sys/class/net/events/drv_start/ ... /sys/class/net/events/stop_queue