Cc'ing relevant people.. On Fri, Mar 7, 2014 at 11:49 PM, Patrik Lundquist <patrik.lundquist@xxxxxxxxx> wrote: > 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@xxxxxxxxx> > 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 > -- > To unsubscribe from this list: send the line "unsubscribe cpufreq" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
