1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
choice
prompt "CPU scheduler runqueue sharing"
default RQ_MC if SCHED_MUQSS
default RQ_NONE
config RQ_NONE
bool "No sharing"
help
This is the default behaviour where the CPU scheduler has one runqueue
per CPU, whether it is a physical or logical CPU (hyperthread).
This can still be enabled runtime with the boot parameter
rqshare=none
If unsure, say N.
config RQ_SMT
bool "SMT (hyperthread) siblings"
depends on SCHED_SMT && SCHED_MUQSS
help
With this option enabled, the CPU scheduler will have one runqueue
shared by SMT (hyperthread) siblings. As these logical cores share
one physical core, sharing the runqueue resource can lead to decreased
overhead, lower latency and higher throughput.
This can still be enabled runtime with the boot parameter
rqshare=smt
If unsure, say N.
config RQ_MC
bool "Multicore siblings"
depends on SCHED_MC && SCHED_MUQSS
help
With this option enabled, the CPU scheduler will have one runqueue
shared by multicore siblings in addition to any SMT siblings.
As these physical cores share caches, sharing the runqueue resource
will lead to lower latency, but its effects on overhead and throughput
are less predictable. As a general rule, 6 or fewer cores will likely
benefit from this, while larger CPUs will only derive a latency
benefit. If your workloads are primarily single threaded, this will
possibly worsen throughput. If you are only concerned about latency
then enable this regardless of how many cores you have.
This can still be enabled runtime with the boot parameter
rqshare=mc
If unsure, say Y.
config RQ_SMP
bool "Symmetric Multi-Processing"
depends on SMP && SCHED_MUQSS
help
With this option enabled, the CPU scheduler will have one runqueue
shared by all physical CPUs unless they are on separate NUMA nodes.
As physical CPUs usually do not share resources, sharing the runqueue
will normally worsen throughput but improve latency. If you only
care about latency enable this.
This can still be enabled runtime with the boot parameter
rqshare=smp
If unsure, say N.
config RQ_ALL
bool "NUMA"
depends on SMP && SCHED_MUQSS
help
With this option enabled, the CPU scheduler will have one runqueue
regardless of the architecture configuration, including across NUMA
nodes. This can substantially decrease throughput in NUMA
configurations, but light NUMA designs will not be dramatically
affected. This option should only be chosen if latency is the prime
concern.
This can still be enabled runtime with the boot parameter
rqshare=all
If unsure, say N.
endchoice
config SHARERQ
int
default 0 if RQ_NONE
default 1 if RQ_SMT
default 2 if RQ_MC
default 3 if RQ_SMP
default 4 if RQ_ALL
|
