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From: Patrik Lundquist <patrik.lundquist@gmail.com>
To: cpufreq@vger.kernel.org
Subject: v3.13.5 intel_pstate: cpufreq: __cpufreq_add_dev: ->get() failed
Date: Fri, 7 Mar 2014 16:49:45 +0100	[thread overview]
Message-ID: <CAA7pwKNmosWaWPR0x3kNzL7eNLk8vdCB=NknU9ayLT9s1fJQYA@mail.gmail.com> (raw)

Hi,

booting 3.13.5 on a dual socket Ivy Bridge-EP resulted in this error:

[    0.194139] smpboot: CPU0: Intel(R) Xeon(R) CPU E5-2687W v2 @
3.40GHz (fam: 06, model: 3e, stepping: 04)
...
[    0.246755] x86: Booting SMP configuration:
[    0.250935] .... node  #0, CPUs:        #1  #2  #3  #4  #5  #6  #7
[    0.357648] .... node  #1, CPUs:    #8  #9 #10 #11 #12 #13 #14 #15
[    0.553293] x86: Booted up 2 nodes, 16 CPUs
[    0.557666] smpboot: Total of 16 processors activated (108850.19 BogoMIPS)
...
[    5.210204] Intel P-state driver initializing.
[    5.232407] Intel pstate controlling: cpu 0
[    5.253628] Intel pstate controlling: cpu 1
[    5.274899] cpufreq: __cpufreq_add_dev: ->get() failed
[    5.294856] Intel pstate controlling: cpu 2
[    5.313553] Intel pstate controlling: cpu 3
[    5.332526] Intel pstate controlling: cpu 4
[    5.352347] Intel pstate controlling: cpu 5
[    5.372112] Intel pstate controlling: cpu 6
[    5.391097] Intel pstate controlling: cpu 7
[    5.410272] Intel pstate controlling: cpu 8
[    5.429092] Intel pstate controlling: cpu 9
[    5.447714] Intel pstate controlling: cpu 10
[    5.465872] Intel pstate controlling: cpu 11
[    5.482942] Intel pstate controlling: cpu 12
[    5.498414] Intel pstate controlling: cpu 13
[    5.513586] Intel pstate controlling: cpu 14
[    5.529200] Intel pstate controlling: cpu 15

CPU 1 is alive and well but missing the cpufreq driver. The system is
running fine otherwise.

Looking closer at the problem gives that intel_pstate_init_cpu() is
successful but intel_pstate_get(), which is called right after by
cpufreq, fails.

Since all_cpu_data[1] is initialized it gives that sample->freq must
be zero. So the bug should be in intel_pstate_calc_busy() which
incorrectly sets sample->freq to zero.

I guess cpu->pstate.max_pstate == 4000000 since that's what
cpuinfo_max_freq and scaling_max_freq is on the other cores.

So the error is likely that core_pct is calculated to 0 in
intel_pstate.c:intel_pstate_calc_busy():

    core_pct = div64_u64(int_tofp(sample->aperf * 100),
                 sample->mperf);



Might be fixed by this commit but should be backported in that case:

commit fcb6a15c2e7e76d493e6f91ea889ab40e1c643a4
Author: Dirk Brandewie <dirk.j.brandewie@intel.com>
Date:   Mon Feb 3 08:55:31 2014 -0800

    intel_pstate: Take core C0 time into account for core busy calculation



My options to explore the problem further by backporting patches and
continuous reboots are a bit limited at the moment.

Regards,
Patrik

             reply	other threads:[~2014-03-07 15:49 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-07 15:49 Patrik Lundquist [this message]
2014-03-10  5:23 ` v3.13.5 intel_pstate: cpufreq: __cpufreq_add_dev: ->get() failed Viresh Kumar
2014-03-10 12:15   ` Patrik Lundquist
2014-03-11 17:58 ` Dirk Brandewie
2014-03-11 19:50   ` Rafael J. Wysocki
2014-03-11 20:08     ` Dirk Brandewie
2014-03-11 20:45       ` Rafael J. Wysocki
2014-03-12  5:21       ` Viresh Kumar
2014-03-12 11:09         ` Rafael J. Wysocki
2014-03-11 20:20   ` Rafael J. Wysocki
2014-03-11 20:17     ` Dirk Brandewie
2014-03-11 20:52       ` Rafael J. Wysocki
2014-03-11 20:57         ` Rafael J. Wysocki
2014-03-11 20:55           ` Dirk Brandewie
2014-03-11 22:48             ` Rafael J. Wysocki
2014-03-11 23:07               ` Rafael J. Wysocki
2014-03-11 23:09                 ` Rafael J. Wysocki
2014-03-11 23:53                   ` Rafael J. Wysocki
2014-03-12  5:22                     ` Viresh Kumar
2014-03-12 11:42                 ` Patrik Lundquist
2014-03-12 13:27                   ` Rafael J. Wysocki
2014-03-12 14:14                   ` Patrik Lundquist
2014-03-12 23:30                     ` [PATCH] cpufreq: Skip current frequency initialization for ->setpolicy drivers Rafael J. Wysocki
2014-03-12 23:30                       ` Dirk Brandewie
2014-03-18 11:53                       ` Srivatsa S. Bhat
2014-03-12  5:25           ` v3.13.5 intel_pstate: cpufreq: __cpufreq_add_dev: ->get() failed Viresh Kumar
2014-03-12 11:03             ` Rafael J. Wysocki
2014-03-11 22:07   ` Patrik Lundquist

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