Feature request: offline CPU handling #873
Description
Host operating system: output of uname -a
Linux xxxx 3.10.0-693.2.2.el7.ppc64le #1 SMP Sat Sep 9 03:58:38 EDT 2017 ppc64le ppc64le ppc64le GNU/Linux
node_exporter version: output of node_exporter --version
node_exporter, version 0.16.0-rc.0 (branch: build, revision: 8ec35dfcd0aaa05b6039fc3c4bef7a675d419f6b)
go version: go1.10
node_exporter command line flags
default
Are you running node_exporter in Docker?
no
What did you do that produced an error?
none
What did you expect to see?
This PPC server has SMT=2 (Simultaneous multithreading) which can scale on-the-fly up to 8x.
# ppc64_cpu --smt
SMT=2
# ppc64_cpu --info
Core 0: 0* 1* 2 3 4 5 6 7
Core 1: 8* 9* 10 11 12 13 14 15
Core 2: 16* 17* 18 19 20 21 22 23
Core 3: 24* 25* 26 27 28 29 30 31
Core 4: 32* 33* 34 35 36 37 38 39
Core 5: 40* 41* 42 43 44 45 46 47
Core 6: 48* 49* 50 51 52 53 54 55
Core 7: 56* 57* 58 59 60 61 62 63
Core 8: 64* 65* 66 67 68 69 70 71
Core 9: 72* 73* 74 75 76 77 78 79
Core 10: 80* 81* 82 83 84 85 86 87
Core 11: 88* 89* 90 91 92 93 94 95
Core 12: 96* 97* 98 99 100 101 102 103
Core 13: 104* 105* 106 107 108 109 110 111
Core 14: 112* 113* 114 115 116 117 118 119
Core 15: 120* 121* 122 123 124 125 126 127
Core 16: 128* 129* 130 131 132 133 134 135
Core 17: 136* 137* 138 139 140 141 142 143
Core 18: 144* 145* 146 147 148 149 150 151
Core 19: 152* 153* 154 155 156 157 158 159
# lscpu
Architecture: ppc64le
Byte Order: Little Endian
CPU(s): 160
On-line CPU(s) list: 0,1,8,9,16,17,24,25,32,33,40,41,48,49,56,57,64,65,72,73,80,81,88,89,96,97,104,105,112,113,120,121,128,129,136,137,144,145,152,153
Off-line CPU(s) list: 2-7,10-15,18-23,26-31,34-39,42-47,50-55,58-63,66-71,74-79,82-87,90-95,98-103,106-111,114-119,122-127,130-135,138-143,146-151,154-159
Thread(s) per core: 2
Core(s) per socket: 5
Socket(s): 4
NUMA node(s): 4
Model: 2.1 (pvr 004b 0201)
Model name: POWER8E (raw), altivec supported
L1d cache: 64K
L1i cache: 32K
L2 cache: 512K
L3 cache: 8192K
NUMA node0 CPU(s): 0,1,8,9,16,17,24,25,32,33
NUMA node1 CPU(s): 40,41,48,49,56,57,64,65,72,73
NUMA node16 CPU(s): 80,81,88,89,96,97,104,105,112,113
NUMA node17 CPU(s): 120,121,128,129,136,137,144,145,152,153
# ppc64_cpu --smt=8
# ppc64_cpu --info
Core 0: 0* 1* 2* 3* 4* 5* 6* 7*
Core 1: 8* 9* 10* 11* 12* 13* 14* 15*
Core 2: 16* 17* 18* 19* 20* 21* 22* 23*
Core 3: 24* 25* 26* 27* 28* 29* 30* 31*
Core 4: 32* 33* 34* 35* 36* 37* 38* 39*
Core 5: 40* 41* 42* 43* 44* 45* 46* 47*
Core 6: 48* 49* 50* 51* 52* 53* 54* 55*
Core 7: 56* 57* 58* 59* 60* 61* 62* 63*
Core 8: 64* 65* 66* 67* 68* 69* 70* 71*
Core 9: 72* 73* 74* 75* 76* 77* 78* 79*
Core 10: 80* 81* 82* 83* 84* 85* 86* 87*
Core 11: 88* 89* 90* 91* 92* 93* 94* 95*
Core 12: 96* 97* 98* 99* 100* 101* 102* 103*
Core 13: 104* 105* 106* 107* 108* 109* 110* 111*
Core 14: 112* 113* 114* 115* 116* 117* 118* 119*
Core 15: 120* 121* 122* 123* 124* 125* 126* 127*
Core 16: 128* 129* 130* 131* 132* 133* 134* 135*
Core 17: 136* 137* 138* 139* 140* 141* 142* 143*
Core 18: 144* 145* 146* 147* 148* 149* 150* 151*
Core 19: 152* 153* 154* 155* 156* 157* 158* 159*
# lscpu
Architecture: ppc64le
Byte Order: Little Endian
CPU(s): 160
On-line CPU(s) list: 0-159
Thread(s) per core: 8
Core(s) per socket: 5
Socket(s): 4
NUMA node(s): 4
Model: 2.1 (pvr 004b 0201)
Model name: POWER8E (raw), altivec supported
L1d cache: 64K
L1i cache: 32K
L2 cache: 512K
L3 cache: 8192K
NUMA node0 CPU(s): 0-39
NUMA node1 CPU(s): 40-79
NUMA node16 CPU(s): 80-119
NUMA node17 CPU(s): 120-159
In the 'SMT=2' case there are 960 metrics we could ignore (4 sockets * 5 cores * 6 (8-2) threads * 8 modes).
# curl -s localhost:9100/metrics | egrep -w -v -e '(HELP|TYPE)' | grep node_cpu_seconds_total | wc -l
1280
My feature request is to reduce the amount of CPU metrics. There are 2 alternatives that come to mind,
- Ignoring the offline CPUs in the node_exporter
- Introducing a new label, online="0|1", and filtering during Prometheus scrape process.
What did you want to see instead?
# curl -s localhost:9100/metrics | egrep -w -v -e '(HELP|TYPE)' | grep node_cpu_seconds_total | grep 'online=1 ' | wc -l
320