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Message-ID: <20090810201406.GA6961@elte.hu> Date: Mon, 10 Aug 2009 22:14:06 +0200 From: Ingo Molnar <mingo@...e.hu> To: Johannes Stezenbach <js@...21.net>, Robert Richter <robert.richter@....com>, Steven Rostedt <rostedt@...dmis.org> Cc: Andi Kleen <andi@...stfloor.org>, x86@...nel.org, linux-kernel@...r.kernel.org, "Rafael J. Wysocki" <rjw@...k.pl> Subject: Re: 2.6.31-rc5 regression: x86 MCE malfunction on Thinkpad T42p * Johannes Stezenbach <js@...21.net> wrote: > On Mon, Aug 10, 2009 at 03:29:23PM +0200, Ingo Molnar wrote: > > * Johannes Stezenbach <js@...21.net> wrote: > > > On Mon, Aug 10, 2009 at 02:32:28PM +0200, Andi Kleen wrote: > > > > > > > > When the BIOS doesn't enable it then force enabling lapic might not work. > > > > > > > > This could cause either boot failures (obvious) or more subtle > > > > problems like SMM doing something unexpected. Just saying that > > > > if you have strange problems later first try disabling this > > > > option again. > > > > > > Thanks for the heads-up. I remember I tried to use oprofile in > > > the past on this machine and was disappointed that it only got the > > > timer event. I'll keep lapic for now unless I see signs of > > > instability. > > > > What's the output of something like 'perf stat true', and does 'perf > > top' output something - i.e. do perfcounters work in general? Once > > you get to that stage and it works then it should be fine. > > # ./perf stat true > > Performance counter stats for 'true': > > 0.985808 task-clock-msecs # 0.779 CPUs > 0 context-switches # 0.000 M/sec > 0 CPU-migrations # 0.000 M/sec > 110 page-faults # 0.112 M/sec > 583873 cycles # 592.279 M/sec > 500937 instructions # 0.858 IPC > <not counted> cache-references > <not counted> cache-misses > > 0.001265524 seconds time elapsed That looks almost normal - except for cache-references and cache-misses that is not counted. Could you send the /proc/cpuinfo info please? > > > # ./perf top > ------------------------------------------------------------------------------ > PerfTop: 172 irqs/sec kernel:43.6% [100000 cycles], (all, 1 CPUs) > ------------------------------------------------------------------------------ > > samples pcnt RIP kernel function > ______ _______ _____ ________________ _______________ > > 96.00 - 16.4% - 00000000c129be10 : acpi_pm_read > 66.00 - 11.3% - 00000000c116fbb1 : delay_tsc > 59.00 - 10.1% - 00000000c1172a83 : ioread32 > 26.00 - 4.4% - 00000000c116f567 : vsnprintf > 21.00 - 3.6% - 00000000c11a4721 : acpi_os_read_port > 20.00 - 3.4% - 00000000c136612c : schedule > 19.00 - 3.2% - 00000000c10054b9 : mask_and_ack_8259A > 18.00 - 3.1% - 00000000c11ce8bc : acpi_idle_enter_bm > 17.00 - 2.9% - 00000000c1090dd1 : do_select > 16.00 - 2.7% - 00000000c133f380 : unix_poll > 14.00 - 2.4% - 00000000c116e2b4 : number > 13.00 - 2.2% - 00000000c1002847 : sysenter_past_esp > 10.00 - 1.7% - 00000000c1085b84 : fget_light > 9.00 - 1.5% - 00000000c13666a7 : preempt_schedule > 9.00 - 1.5% - 00000000c102cf1b : get_next_timer_interrupt > ^C Ok, this looks normal. > First I tried oprofile while running an endless while loop in bash: > > # opreport > CPU: Pentium M (P6 core), speed 1800 MHz (estimated) > Counted CPU_CLK_UNHALTED events (clocks processor is not halted, and not in a thermal trip) with a unit mask of 0x00 (No unit mask) count 100000 > CPU_CLK_UNHALT...| > samples| %| > ------------------ > 282940 76.5545 bash > 78266 21.1763 libc-2.9.so > 1730 0.4681 Xorg > 1069 0.2892 oprofiled > > Looks plausible. Yeah. > But in demsg I got this: > > Delta way too big! 18446744022868427516 ts=18446744022868427516 write stamp = 0 > ------------[ cut here ]------------ > WARNING: at kernel/trace/ring_buffer.c:1392 rb_reserve_next_event+0x150/0x309() > Hardware name: 2373Y4M > Modules linked in: ath5k mac80211 ath cfg80211 oprofile bnep sco rfcomm l2cap bluetooth ehci_hcd uhci_hc > Pid: 13478, comm: opcontrol Not tainted 2.6.31-rc5 #5 > Call Trace: > [<c10248dd>] warn_slowpath_common+0x60/0x90 > [<c102491a>] warn_slowpath_null+0xd/0x10 > [<c1054129>] rb_reserve_next_event+0x150/0x309 > [<c1068c06>] ? get_page_from_freelist+0x86/0x35a > [<c10544f7>] ring_buffer_lock_reserve+0xe7/0x135 > [<f88622c0>] op_cpu_buffer_write_reserve+0x1a/0x4b [oprofile] > [<f886239d>] op_add_code+0x57/0x98 [oprofile] > [<c1068c06>] ? get_page_from_freelist+0x86/0x35a > [<c1367c08>] ? page_fault+0x0/0x8 > [<f8862409>] log_sample+0x2b/0x6c [oprofile] > [<c1064c76>] ? filemap_fault+0x74/0x32b > [<f886249c>] oprofile_add_sample+0x3b/0x6b [oprofile] > [<f88641d8>] ppro_check_ctrs+0x66/0xdb [oprofile] > [<c1074bde>] ? __do_fault+0x303/0x32f > [<f8863907>] profile_exceptions_notify+0x1f/0x26 [oprofile] > [<c103953b>] notifier_call_chain+0x2b/0x55 > [<c10398e3>] __atomic_notifier_call_chain+0x1a/0x3a > [<c103990f>] atomic_notifier_call_chain+0xc/0xe > [<c103993e>] notify_die+0x2d/0x2f > [<c1003c54>] do_nmi+0x63/0x222 > [<c1367d1d>] nmi_stack_correct+0x28/0x2d > [<c1367c08>] ? page_fault+0x0/0x8 > ---[ end trace d174f39c63495e01 ]--- That's a new warning i havent seen before - i've Cc:-ed Robert (oprofile maintainer) and Steve (ftrace/ring-buffer maintainer) for that. The warning is probably harmless - oprofile sampling still works fine, right? Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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