perf-kvm - Online in the Cloud

PROGRAM:

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 (x86 only) and ioport (x86 only)
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 (x86 only), ioport (x86 only).
(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 (x86 only), ioport (x86 only).
(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 (x86 only) or Wait state (s390 only) 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.

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