Best Practices When Deploying Linux on the HP ProLiant DL980 (updated December 2012)
4
Note
The following pages contain numerous examples. The text displayed in the
examples may differ from what you see in your specific environment, depending
on the configuration of your system and the OS version used.
Linux hardware overview
CPU mappings
Linux uses the /proc/cpuinfo file to enumerate logical processors. As an example, Table 1 shows the logical
processor assignments for the first two processors of a 64-core DL980 (8 processors with 8 cores per processor) with
Hyper-Threading enabled. The Physical ID corresponds to the physical processor socket. Core ID is the processing core
on a particular physical processor. Thus, logical processor numbers 0 and 64 are the two threads on the first core on the
first physical processor. When using the numactl and taskset commands for process and memory object placement
(as discussed in the following two sections, respectively: “Controlling tasks and memory object placement” and “Moving
tasks to other NUMA nodes”), refer to the information in the /proc/cpuinfo file. For more information about these
commands, see the numactl(8) and taskset(1) manpages.
Table 1: Logical processor assignments
Logical
Processor
Physical
ID
Core
ID
Logical
Processor
Physical
ID
Core
ID
0
0
0
64
0
0
1
0
1
65
0
1
2
0
2
66
0
2
3
0
4
67
0
4
4
0
5
68
0
5
5
0
7
69
0
7
6
0
8
70
0
8
7
0
9
71
0
9
8
1
0
72
1
0
9
1
1
73
1
1
10
1
2
74
1
2
11
1
3
75
1
3
12
1
6
76
1
6
13
1
7
77
1
7
14
1
8
78
1
49
15
1
9
79
1
9
PCI slot mappings
PCI slot bus numbers are documented in the HP ProLiant DL980 QuickSpecs. You can use the document to map a
particular I/O slot to its corresponding PCI device listed by the lspci command. If your kernel populates the
/sys/bus/pci/slots hierarchy (as does Red Hat Enterprise Linux 6, for example), you can also obtain the bus
number associated with each slot from the /sys/bus/pci/slots/<slot number>/address file. The following
example shows a dual-port Fibre Channel HBA using bus 0x0b, which maps to slots 9:
cat /sys/bus/pci/slots/9/address
0000:0b:00
lspci | grep 0b:00