Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754699Ab3DKLeQ (ORCPT ); Thu, 11 Apr 2013 07:34:16 -0400 Received: from relay1.sgi.com ([192.48.179.29]:42221 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752087Ab3DKLeP (ORCPT ); Thu, 11 Apr 2013 07:34:15 -0400 Date: Thu, 11 Apr 2013 06:34:13 -0500 From: Robin Holt To: Ingo Molnar Cc: Robin Holt , Russ Anderson , Linus Torvalds , "H. Peter Anvin" , Andrew Morton , Linux Kernel Mailing List , Shawn Guo , Thomas Gleixner , Ingo Molnar , the arch/x86 maintainers Subject: Re: [PATCH] Do not force shutdown/reboot to boot cpu. Message-ID: <20130411113412.GP3658@sgi.com> References: <20130408165916.GA3672@sgi.com> <20130410111620.GB29752@gmail.com> <20130410152911.GA3011@sgi.com> <20130410165934.GB21951@gmail.com> <20130410171420.GF3658@sgi.com> <20130410172236.GE21951@gmail.com> <20130410175519.GG3658@sgi.com> <20130410190003.GH3658@sgi.com> <20130411085751.GD11824@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130411085751.GD11824@gmail.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2418 Lines: 43 > Ok, so it looks profilable. > > The result above is not surprising: most CPUs sit in idle and don't do anything, > while the loop goes on, right? > > The interesting thing to profile would be the parallel bring-down, with the > simplest global lock solution you mentioned. In that case most CPUs should be > doing 'something' all the time - maybe spinning on the lock, maybe something else, > right? Again, mostly looks idle. Events: 5M cycles 31.69% swapper [kernel.kallsyms] [k] update_cfs_rq_blocked_load 14.22% swapper [kernel.kallsyms] [k] load_balance 12.95% swapper [kernel.kallsyms] [k] ktime_get 4.64% swapper [kernel.kallsyms] [k] idle_cpu 3.46% swapper [kernel.kallsyms] [k] uv_read_rtc 2.26% swapper [kernel.kallsyms] [k] ktime_get_update_offsets 2.25% swapper [kernel.kallsyms] [k] rcu_check_callbacks 1.72% swapper [kernel.kallsyms] [k] _raw_spin_lock_irqsave 1.57% swapper [kernel.kallsyms] [k] native_write_msr_safe 1.53% swapper [kernel.kallsyms] [k] native_safe_halt 1.52% swapper [kernel.kallsyms] [k] apic_timer_interrupt 1.52% swapper [kernel.kallsyms] [k] update_blocked_averages 1.51% swapper [kernel.kallsyms] [k] __lock_text_start 1.48% swapper [kernel.kallsyms] [k] rcu_process_gp_end 1.40% swapper [kernel.kallsyms] [k] rcu_process_callbacks 1.19% reboot [kernel.kallsyms] [k] kmem_cache_alloc_node 0.63% swapper [kernel.kallsyms] [k] check_for_new_grace_period 0.58% swapper [kernel.kallsyms] [k] rebalance_domains 0.55% swapper [kernel.kallsyms] [k] cpumask_next_and 0.54% swapper [kernel.kallsyms] [k] __tick_nohz_idle_enter 0.53% swapper [kernel.kallsyms] [k] perf_adjust_freq_unthr_context 0.49% swapper [kernel.kallsyms] [k] _raw_spin_lock Robin -- 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/