Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754964AbYAEKTm (ORCPT ); Sat, 5 Jan 2008 05:19:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753010AbYAEKTc (ORCPT ); Sat, 5 Jan 2008 05:19:32 -0500 Received: from gate.crashing.org ([63.228.1.57]:35344 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752977AbYAEKTb (ORCPT ); Sat, 5 Jan 2008 05:19:31 -0500 Subject: Re: Idle loadavg of ~1, maybe MD related From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org To: "Robin H. Johnson" Cc: Andrew Morton , linux-kernel@vger.kernel.org, Paul Mackerras In-Reply-To: <20080105100455.GB911@curie-int.orbis-terrarum.net> References: <20071230100614.GX17327@curie-int.orbis-terrarum.net> <20080105013037.a354b33a.akpm@linux-foundation.org> <20080105100455.GB911@curie-int.orbis-terrarum.net> Content-Type: text/plain Date: Sat, 05 Jan 2008 21:18:52 +1100 Message-Id: <1199528332.7291.53.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.12.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3003 Lines: 58 On Sat, 2008-01-05 at 02:04 -0800, Robin H. Johnson wrote: > On Sat, Jan 05, 2008 at 01:30:37AM -0800, Andrew Morton wrote: > > >From that I'd suspect that kwindfarm is being a bad citizen. > > If a process is consistently stuck in D state, run > Windfarm. It's an unfortunate artifact that kernel threads that do non-interruptible sleep are counted as load... In the case of windfarm, it does a lot (a _LOT_) of accesses to various i2c busses and the SMU (the system management unit which controls the fans). All those are done in the form of short requests during which the process is doing a wait_for_completion() or similar. I don't see a better way to do that, I think we could have good use of something that stops counting those in the load average... Ben. > > echo w > /proc/sysrq-trigger > > then record the resulting dmesg output so we can see where it got stuck. > > Traceback: > [552710.416174] SysRq : Show Blocked State > [552710.417876] task PC stack pid father > [552710.417888] kwindfarm D 0000000000000000 0 829 2 > [552710.417892] Call Trace: > [552710.417895] [c00000036c9835f0] [c000000000528b90] 0xc000000000528b90 (unreliable) > [552710.417908] [c00000036c9837c0] [c00000000000f4a8] .__switch_to+0xd8/0x110 > [552710.417985] [c00000036c983850] [c0000000003bb2a0] .schedule+0x62c/0x6c8 > [552710.417992] [c00000036c983940] [c0000000003bb8c4] .schedule_timeout+0x3c/0xe8 > [552710.417997] [c00000036c983a10] [c0000000003bb51c] .wait_for_common+0x100/0x1bc > [552710.418002] [c00000036c983ae0] [c000000000285300] .smu_fan_set+0x17c/0x1e4 > [552710.418009] [c00000036c983c30] [c000000000284078] .pm112_wf_notify+0xc50/0x12d0 > [552710.418015] [c00000036c983d20] [c0000000003bfb84] .notifier_call_chain+0x5c/0xcc > [552710.418021] [c00000036c983dc0] [c00000000006f4b4] .__blocking_notifier_call_chain+0x70/0xb0 > [552710.418027] [c00000036c983e70] [c000000000282d9c] .wf_thread_func+0x78/0x11c > [552710.418032] [c00000036c983f00] [c000000000069b00] .kthread+0x78/0xc4 > [552710.418039] [c00000036c983f90] [c000000000023d0c] .kernel_thread+0x4c/0x68 > [552710.418064] Sched Debug Version: v0.07, 2.6.24-rc6-prod-g6f0f5304 #10 > [552710.418067] now at 552723945.170635 msecs > [552710.418070] .sysctl_sched_latency : 60.000000 > [552710.418073] .sysctl_sched_min_granularity : 12.000000 > [552710.418076] .sysctl_sched_wakeup_granularity : 30.000000 > [552710.418079] .sysctl_sched_batch_wakeup_granularity : 30.000000 > [552710.418082] .sysctl_sched_child_runs_first : 0.000001 > [552710.418085] .sysctl_sched_features : 7 > > Full output at > http://dev.gentoo.org/~robbat2/20080105_windfarm_sysrq_w.txt > -- 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/