Re: Intel Xeon Scalable and CPU frequency scaling on NVMe/SSD Ceph OSDs

John Hearns <hearnsj@xxxxxxxxxxxxxx> · Wed, 16 May 2018 13:29:21 +0200

Blair,
   methinks someone is doing bitcoin mining on your systems when they are idle   :-)

I WAS going to say that maybe the cpupower utility needs an update to cope with that generation of CPUs.
But 7proc/cpuinfo never lies  (does it ?)

On 16 May 2018 at 13:22, Blair Bethwaite <blair.bethwaite@xxxxxxxxx> wrote:
On 15 May 2018 at 08:45, Wido den Hollander <wido@xxxxxxxx> wrote:
> We've got some Skylake Ubuntu based hypervisors that we can look at to

> compare tomorrow...

> 

Awesome!

Ok, so results still inconclusive I'm afraid...

The Ubuntu machines we're looking at (Dell R740s and C6420s running with Performance BIOS power profile, which amongst other things disables cstates and enables turbo) are currently running either a 4.13 or a 4.15 HWE kernel - we needed 4.13 to support PERC10 and even get them booting from local storage, then 4.15 to get around a prlimit bug that was breaking Nova snapshots, so here we are. Where are you getting 4.16, http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.16/ ?

So interestingly in our case we seem to have no cpufreq driver loaded. After installing linux-generic-tools (cause cpupower is supposed to supersede cpufrequtils I think?):

rr42-03:~$ uname -a
Linux rcgpudc1rr42-03 4.15.0-13-generic #14~16.04.1-Ubuntu SMP Sat Mar 17 03:04:59 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

rr42-03:~$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-4.15.0-13-generic root=/dev/mapper/vg00-root ro intel_iommu=on iommu=pt intel_idle.max_cstate=0 processor.max_cstate=1

rr42-03:~$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little EndianCPU(s):                36
On-line CPU(s) list:   0-35
Thread(s) per core:    1
Core(s) per socket:    18
Socket(s):             2
NUMA node(s):          2
Vendor ID:             GenuineIntel
CPU family:            6Model:                 85
Model name:            Intel(R) Xeon(R) Gold 6150 CPU @ 2.70GHz
Stepping:              4
CPU MHz:               3400.956
BogoMIPS:              5401.45
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32KL2 cache:              1024K
L3 cache:              25344K
NUMA node0 CPU(s):     0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34
NUMA node1 CPU(s):     1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 cdp_l3 invpcid_single pti intel_ppin mba tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm cqm mpx rdt_a avx512f avx512dq rdseed adx smap clflushopt clwb intel_pt avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local ibpb ibrs stibp dtherm ida arat pln pts pku ospke

rr42-03:~$ sudo cpupower frequency-info
analyzing CPU 0:
  no or unknown cpufreq driver is active on this CPU
  CPUs which run at the same hardware frequency: Not Available
  CPUs which need to have their frequency coordinated by software: Not Available
  maximum transition latency:  Cannot determine or is not supported.Not Available
  available cpufreq governors: Not Available
  Unable to determine current policy
  current CPU frequency: Unable to call hardware
  current CPU frequency:  Unable to call to kernel
  boost state support:
    Supported: yes
    Active: yes

And of course there is nothing under sysfs (/sys/devices/system/cpu*). But /proc/cpuinfo and cpupower-monitor show that we seem to be hitting turbo freqs:

rr42-03:~$ sudo cpupower monitor
              |Nehalem                    || Mperf
PKG |CORE|CPU | C3   | C6   | PC3  | PC6  || C0   | Cx   | Freq
   0|   0|   0|  0.00|  0.00|  0.00|  0.00||  0.05| 99.95|  3391
   0|   1|   4|  0.00|  0.00|  0.00|  0.00||  0.02| 99.98|  3389
   0|   2|   8|  0.00|  0.00|  0.00|  0.00||  0.14| 99.86|  3067
   0|   3|   6|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3385
   0|   4|   2|  0.00|  0.00|  0.00|  0.00||  0.09| 99.91|  3119
   0|   8|  12|  0.00|  0.00|  0.00|  0.00||  0.03| 99.97|  3312
   0|   9|  16|  0.00|  0.00|  0.00|  0.00||  0.11| 99.89|  3157
   0|  10|  14|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3352
   0|  11|  10|  0.00|  0.00|  0.00|  0.00||  0.05| 99.95|  3390
   0|  16|  20|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3387
   0|  17|  24|  0.00|  0.00|  0.00|  0.00||  0.22| 99.78|  3115
   0|  18|  26|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3389
   0|  19|  22|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3366
   0|  20|  18|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3392
   0|  24|  28|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3376
   0|  25|  32|  0.00|  0.00|  0.00|  0.00||  0.05| 99.95|  3390
   0|  26|  34|  0.00|  0.00|  0.00|  0.00||  0.03| 99.97|  3391
   0|  27|  30|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3392
   1|   0|   1|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3394
   1|   1|   5|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3378
   1|   2|   9|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3393
   1|   3|   7|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3384
   1|   4|   3|  0.00|  0.00|  0.00|  0.00||  0.02| 99.98|  3391
   1|   8|  13|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3390
   1|   9|  17|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3391
   1|  10|  15|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3360
   1|  11|  11|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3393
   1|  16|  21|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3397
   1|  17|  25|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3391
   1|  18|  27|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3376
   1|  19|  23|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3334
   1|  20|  19|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3387
   1|  24|  29|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3377
   1|  25|  33|  0.00|  0.00|  0.00|  0.00||  0.01| 99.99|  3387
   1|  26|  35|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3392
   1|  27|  31|  0.00|  0.00|  0.00|  0.00||  0.00|100.00|  3392

On a similar node with the 4.13 kernel we get similar reports from cpupower-monitor, but oddly on 4.13 /proc/cpuinfo shows all cores at base 2700.000 (on 4.15 it updates).

We can try 4.16 tomorrow. But I wonder why we are already seeing turbo even at idle and you aren't... only thing I can think of is that it must be because our cstates are disabled in BIOS, indeed when looking in dmesg I see:

[    1.274325] intel_idle: disabled

So it stands to reason that intel_idle.max_cstate=0 is doing nothing for either of us. What do you see from intel_idle on 4.16?

-- 
Cheers,
~Blairo

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