table of contents
PERF-KVM(1) | perf Manual | PERF-KVM(1) |
NAME¶
perf-kvm - Tool to trace/measure kvm guest os
SYNOPSIS¶
perf kvm [--host] [--guest] [--guestmount=<path>
[--guestkallsyms=<path> --guestmodules=<path> | --guestvmlinux=<path>]]
{top|record|report|diff|buildid-list} [<options>] perf kvm [--host] [--guest] [--guestkallsyms=<path> --guestmodules=<path>
| --guestvmlinux=<path>] {top|record|report|diff|buildid-list|stat} [<options>] 'perf kvm stat [record|report|live] [<options>]
DESCRIPTION¶
There are a couple of variants of perf kvm:
'perf kvm [options] top <command>' to generates and displays a performance counter profile of guest os in realtime of an arbitrary workload.
'perf kvm record <command>' to record the performance counter profile of an arbitrary workload and save it into a perf data file. We set the default behavior of perf kvm as --guest, so if neither --host nor --guest is input, the perf data file name is perf.data.guest. If --host is input, the perf data file name is perf.data.kvm. If you want to record data into perf.data.host, please input --host --no-guest. The behaviors are shown as following:
Default('') -> perf.data.guest
--host -> perf.data.kvm
--guest -> perf.data.guest
--host --guest -> perf.data.kvm
--host --no-guest -> perf.data.host
'perf kvm report' to display the performance counter profile information recorded via perf kvm record.
'perf kvm diff' to displays the performance difference amongst two perf.data files captured via perf record.
'perf kvm buildid-list' to display the buildids found in a perf data file, so that other tools can be used to fetch packages with matching symbol tables for use by perf report. As buildid is read from /sys/kernel/notes in os, then if you want to list the buildid for guest, please make sure your perf data file was captured with --guestmount in perf kvm record.
'perf kvm stat <command>' to run a command and gather performance counter statistics. Especially, perf 'kvm stat record/report' generates a statistical analysis of KVM events. Currently, vmexit, mmio and ioport events are supported. 'perf kvm stat record <command>' records kvm events and the events between start and end <command>. And this command produces a file which contains tracing results of kvm events.
'perf kvm stat report' reports statistical data which includes events handled time, samples, and so on.
'perf kvm stat live' reports statistical data in a live mode (similar to record + report but with statistical data updated live at a given display rate).
OPTIONS¶
-i, --input=<path>
Input file name.
-o, --output=<path>
Output file name.
--host
Collect host side performance profile.
--guest
Collect guest side performance profile.
--guestmount=<path>
Guest os root file system mount directory. Users mounts
guest os root directories under <path> by a specific filesystem access
method, typically, sshfs. For example, start 2 guest os. The one’s pid
is 8888 and the other’s is 9999. #mkdir /guestmount; cd/guestmount
#sshfs -o allow_other,direct_io -p 5551 localhost:/ 8888/ #sshfs -o
allow_other,direct_io -p 5552 localhost:/ 9999/ #perf kvm --host --guest
--guestmount=~/guestmount top
--guestkallsyms=<path>
Guest os /proc/kallsyms file copy. perf kvm' reads
it to get guest kernel symbols. Users copy it out from guest os.
--guestmodules=<path>
Guest os /proc/modules file copy. perf kvm' reads
it to get guest kernel module information. Users copy it out from guest
os.
--guestvmlinux=<path>
Guest os kernel vmlinux.
-v, --verbose
Be more verbose (show counter open errors, etc).
STAT REPORT OPTIONS¶
--vcpu=<value>
analyze events which occur on this vcpu. (default: all
vcpus)
--event=<value>
event to be analyzed. Possible values: vmexit, mmio,
ioport. (default: vmexit)
-k, --key=<value>
Sorting key. Possible values: sample (default, sort by
samples number), time (sort by average time).
-p, --pid=
Analyze events only for given process ID(s) (comma
separated list).
STAT LIVE OPTIONS¶
-d, --display
Time in seconds between display updates
-m, --mmap-pages=
Number of mmap data pages (must be a power of two) or
size specification with appended unit character - B/K/M/G. The size is rounded
up to have nearest pages power of two value.
-a, --all-cpus
System-wide collection from all CPUs.
-p, --pid=
Analyze events only for given process ID(s) (comma
separated list).
--vcpu=<value>
analyze events which occur on this vcpu. (default: all
vcpus)
--event=<value>
event to be analyzed. Possible values: vmexit, mmio,
ioport. (default: vmexit)
-k, --key=<value>
Sorting key. Possible values: sample (default, sort by
samples number), time (sort by average time).
--duration=<value>
Show events other than HLT that take longer than duration
usecs.
--proc-map-timeout
When processing pre-existing threads /proc/XXX/mmap, it
may take a long time, because the file may be huge. A time out is needed in
such cases. This option sets the time out limit. The default value is 500
ms.
SEE ALSO¶
perf-top(1), perf-record(1), perf-report(1), perf-diff(1), perf-buildid-list(1), perf-stat(1)
06/04/2024 | perf |