mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-22 16:48:18 +07:00
2438ac954b
Add a document describing the fields provided by /proc/powerpc/vcpudispatch_stats. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
69 lines
2.9 KiB
Plaintext
69 lines
2.9 KiB
Plaintext
VCPU Dispatch Statistics:
|
|
=========================
|
|
|
|
For Shared Processor LPARs, the POWER Hypervisor maintains a relatively
|
|
static mapping of the LPAR processors (vcpus) to physical processor
|
|
chips (representing the "home" node) and tries to always dispatch vcpus
|
|
on their associated physical processor chip. However, under certain
|
|
scenarios, vcpus may be dispatched on a different processor chip (away
|
|
from its home node).
|
|
|
|
/proc/powerpc/vcpudispatch_stats can be used to obtain statistics
|
|
related to the vcpu dispatch behavior. Writing '1' to this file enables
|
|
collecting the statistics, while writing '0' disables the statistics.
|
|
By default, the DTLB log for each vcpu is processed 50 times a second so
|
|
as not to miss any entries. This processing frequency can be changed
|
|
through /proc/powerpc/vcpudispatch_stats_freq.
|
|
|
|
The statistics themselves are available by reading the procfs file
|
|
/proc/powerpc/vcpudispatch_stats. Each line in the output corresponds to
|
|
a vcpu as represented by the first field, followed by 8 numbers.
|
|
|
|
The first number corresponds to:
|
|
1. total vcpu dispatches since the beginning of statistics collection
|
|
|
|
The next 4 numbers represent vcpu dispatch dispersions:
|
|
2. number of times this vcpu was dispatched on the same processor as last
|
|
time
|
|
3. number of times this vcpu was dispatched on a different processor core
|
|
as last time, but within the same chip
|
|
4. number of times this vcpu was dispatched on a different chip
|
|
5. number of times this vcpu was dispatches on a different socket/drawer
|
|
(next numa boundary)
|
|
|
|
The final 3 numbers represent statistics in relation to the home node of
|
|
the vcpu:
|
|
6. number of times this vcpu was dispatched in its home node (chip)
|
|
7. number of times this vcpu was dispatched in a different node
|
|
8. number of times this vcpu was dispatched in a node further away (numa
|
|
distance)
|
|
|
|
An example output:
|
|
$ sudo cat /proc/powerpc/vcpudispatch_stats
|
|
cpu0 6839 4126 2683 30 0 6821 18 0
|
|
cpu1 2515 1274 1229 12 0 2509 6 0
|
|
cpu2 2317 1198 1109 10 0 2312 5 0
|
|
cpu3 2259 1165 1088 6 0 2256 3 0
|
|
cpu4 2205 1143 1056 6 0 2202 3 0
|
|
cpu5 2165 1121 1038 6 0 2162 3 0
|
|
cpu6 2183 1127 1050 6 0 2180 3 0
|
|
cpu7 2193 1133 1052 8 0 2187 6 0
|
|
cpu8 2165 1115 1032 18 0 2156 9 0
|
|
cpu9 2301 1252 1033 16 0 2293 8 0
|
|
cpu10 2197 1138 1041 18 0 2187 10 0
|
|
cpu11 2273 1185 1062 26 0 2260 13 0
|
|
cpu12 2186 1125 1043 18 0 2177 9 0
|
|
cpu13 2161 1115 1030 16 0 2153 8 0
|
|
cpu14 2206 1153 1033 20 0 2196 10 0
|
|
cpu15 2163 1115 1032 16 0 2155 8 0
|
|
|
|
In the output above, for vcpu0, there have been 6839 dispatches since
|
|
statistics were enabled. 4126 of those dispatches were on the same
|
|
physical cpu as the last time. 2683 were on a different core, but within
|
|
the same chip, while 30 dispatches were on a different chip compared to
|
|
its last dispatch.
|
|
|
|
Also, out of the total of 6839 dispatches, we see that there have been
|
|
6821 dispatches on the vcpu's home node, while 18 dispatches were
|
|
outside its home node, on a neighbouring chip.
|