Manual: perf-kvm

PERF-KVM(1)						 perf Manual						 PERF-KVM(1)

NAME
       perf-kvm - Tool to trace/measure kvm guest os

SYNOPSIS
       perf kvm [--host] [--guest] [--guestmount=
	       [--guestkallsyms= --guestmodules= | --guestvmlinux=]]
	       {top|record|report|diff|buildid-list} []
       perf kvm [--host] [--guest] [--guestkallsyms= --guestmodules=
	       | --guestvmlinux=] {top|record|report|diff|buildid-list|stat} []
       'perf kvm stat [record|report|live] []

DESCRIPTION
       There are a couple of variants of perf kvm:

	   'perf kvm [options] top ' to generates and displays
	   a performance counter profile of guest os in realtime
	   of an arbitrary workload.

	   'perf kvm record ' 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 ' 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 ' records kvm events
	   and the events between start and end .
	   And this command produces a file which contains tracing results of kvm
	   events.

	   'perf kvm stat report' reports statistical data which includes events
	   handled sample, percent_sample, time, percent_time, max_t, min_t, mean_t.

	   '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=
	   Input file name, for the report, diff and buildid-list subcommands.

       -o, --output=
	   Output file name, for the record subcommand. Doesn’t work with report, just redirect the output to a file when
	   using report.

       --host
	   Collect host side performance profile.

       --guest
	   Collect guest side performance profile.

       --guestmount=
	   Guest OS root file system mount directory. Users mount guest OS root directories under  by a specific
	   filesystem access method, typically, sshfs. For example, start 2 guest OS, 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=
	   Guest OS /proc/kallsyms file copy. perf reads it to get guest kernel symbols. Users copy it out from guest OS.

       --guestmodules=
	   Guest OS /proc/modules file copy. perf reads it to get guest kernel module information. Users copy it out from
	   guest OS.

       --guestvmlinux=
	   Guest OS kernel vmlinux.

       --guest-code
	   Indicate that guest code can be found in the hypervisor process, which is a common case for KVM test programs.

       --stdio
	   Use the stdio interface.

       -v, --verbose
	   Be more verbose (show counter open errors, etc).

STAT REPORT OPTIONS
       --vcpu=
	   analyze events which occur on this vcpu. (default: all vcpus)

       --event=
	   event to be analyzed. Possible values: vmexit, mmio (x86 only), ioport (x86 only). (default: vmexit)

       -k, --key=
	   Sorting key. Possible values: sample (default, sort by samples number), percent_sample (sort by sample
	   percentage), time (sort by average time), precent_time (sort by time percentage), max_t (sort by maximum time),
	   min_t (sort by minimum time), mean_t (sort by mean 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 in bytes with appended unit character -
	   B/K/M/G. The size is rounded up to the nearest power-of-two page value.

       -a, --all-cpus
	   System-wide collection from all CPUs.

       -p, --pid=
	   Analyze events only for given process ID(s) (comma separated list).

       --vcpu=
	   analyze events which occur on this vcpu. (default: all vcpus)

       --event=
	   event to be analyzed. Possible values: vmexit, mmio (x86 only), ioport (x86 only). (default: vmexit)

       -k, --key=
	   Sorting key. Possible values: sample (default, sort by samples number), time (sort by average time).

       --duration=
	   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.

SEE ALSO
       perf-top(1), perf-record(1), perf-report(1), perf-diff(1), perf-buildid-list(1), perf-stat(1)

perf							 07/31/2026						 PERF-KVM(1)