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Message-ID: <CAP-5=fVW0Hnf6SfuAC4q-bZtr7h7XkYpQrGLQVj6rXc4Ddh5fQ@mail.gmail.com>
Date: Thu, 27 Nov 2025 03:53:13 -0800
From: Ian Rogers <irogers@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
James Clark <james.clark@...aro.org>, Collin Funk <collin.funk1@...il.com>,
Dmitry Vyukov <dvyukov@...gle.com>, Andi Kleen <ak@...ux.intel.com>,
Thomas Falcon <thomas.falcon@...el.com>, Leo Yan <leo.yan@....com>,
Yicong Yang <yangyicong@...ilicon.com>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Masami Hiramatsu (Google)" <mhiramat@...nel.org>, Stephen Brennan <stephen.s.brennan@...cle.com>,
Haibo Xu <haibo1.xu@...el.com>, linux-kernel@...r.kernel.org,
linux-perf-users@...r.kernel.org
Subject: Re: [PATCH v1 17/17] perf test kvm: Add some basic perf kvm test coverage
On Tue, Nov 25, 2025 at 11:21 PM Namhyung Kim <namhyung@...nel.org> wrote:
>
> On Sat, Nov 22, 2025 at 12:19:29AM -0800, Ian Rogers wrote:
> > Setup qemu with KVM then run kvm stat and some host
> > recording/reporting/build-id tests.
> >
> > Signed-off-by: Ian Rogers <irogers@...gle.com>
> > ---
> > tools/perf/tests/shell/kvm.sh | 154 ++++++++++++++++++++++++++++++++++
> > 1 file changed, 154 insertions(+)
> > create mode 100755 tools/perf/tests/shell/kvm.sh
> >
> > diff --git a/tools/perf/tests/shell/kvm.sh b/tools/perf/tests/shell/kvm.sh
> > new file mode 100755
> > index 000000000000..2fafde1a29cc
> > --- /dev/null
> > +++ b/tools/perf/tests/shell/kvm.sh
> > @@ -0,0 +1,154 @@
> > +#!/bin/bash
> > +# perf kvm tests
> > +# SPDX-License-Identifier: GPL-2.0
> > +
> > +set -e
> > +
> > +err=0
> > +perfdata=$(mktemp /tmp/__perf_kvm_test.perf.data.XXXXX)
> > +qemu_pid_file=$(mktemp /tmp/__perf_kvm_test.qemu.pid.XXXXX)
> > +
> > +cleanup() {
> > + rm -f "${perfdata}"
> > + if [ -f "${qemu_pid_file}" ]; then
> > + if [ -s "${qemu_pid_file}" ]; then
> > + qemu_pid=$(cat "${qemu_pid_file}")
> > + if [ -n "${qemu_pid}" ]; then
> > + kill "${qemu_pid}" 2>/dev/null || true
> > + fi
> > + fi
> > + rm -f "${qemu_pid_file}"
> > + fi
> > + trap - EXIT TERM INT
> > +}
> > +
> > +trap_cleanup() {
> > + echo "Unexpected signal in ${FUNCNAME[1]}"
> > + cleanup
> > + exit 1
> > +}
> > +trap trap_cleanup EXIT TERM INT
> > +
> > +skip() {
> > + echo "Skip: $1"
> > + cleanup
> > + exit 2
> > +}
> > +
> > +test_kvm_stat() {
> > + echo "Testing perf kvm stat"
> > +
> > + echo "Recording kvm events for pid ${qemu_pid}..."
> > + if ! perf kvm stat record -p "${qemu_pid}" -o "${perfdata}" sleep 1; then
> > + echo "Failed to record kvm events"
> > + err=1
> > + return
> > + fi
> > +
> > + echo "Reporting kvm events..."
> > + if ! perf kvm -i "${perfdata}" stat report 2>&1 | grep -q "VM-EXIT"; then
> > + echo "Failed to find VM-EXIT in report"
> > + perf kvm -i "${perfdata}" stat report 2>&1
> > + err=1
> > + return
> > + fi
> > +
> > + echo "perf kvm stat test [Success]"
> > +}
> > +
> > +test_kvm_record_report() {
> > + echo "Testing perf kvm record/report"
> > +
> > + echo "Recording kvm profile for pid ${qemu_pid}..."
> > + # Use --host to avoid needing guest symbols/mounts for this simple test
> > + # We just want to verify the command runs and produces data
> > + # We run in background and kill it because 'perf kvm record' appends options
> > + # after the command, which breaks 'sleep' (e.g. it gets '-e cycles').
> > + perf kvm --host record -p "${qemu_pid}" -o "${perfdata}" &
> > + rec_pid=$!
> > + sleep 1
> > + kill -INT "${rec_pid}"
> > + wait "${rec_pid}" || true
> > +
> > + echo "Reporting kvm profile..."
> > + # Check for some standard output from report
> > + if ! perf kvm -i "${perfdata}" report --stdio 2>&1 | grep -q "Event count"; then
> > + echo "Failed to report kvm profile"
> > + perf kvm -i "${perfdata}" report --stdio 2>&1
> > + err=1
> > + return
> > + fi
> > +
> > + echo "perf kvm record/report test [Success]"
> > +}
> > +
> > +test_kvm_buildid_list() {
> > + echo "Testing perf kvm buildid-list"
> > +
> > + # We reuse the perf.data from the previous record test
> > + if ! perf kvm --host -i "${perfdata}" buildid-list 2>&1 | grep -q "."; then
> > + echo "Failed to list buildids"
> > + perf kvm --host -i "${perfdata}" buildid-list 2>&1
> > + err=1
> > + return
> > + fi
> > +
> > + echo "perf kvm buildid-list test [Success]"
> > +}
> > +
> > +setup_qemu() {
> > + # Find qemu
> > + if [ "$(uname -m)" = "x86_64" ]; then
> > + qemu="qemu-system-x86_64"
> > + elif [ "$(uname -m)" = "aarch64" ]; then
> > + qemu="qemu-system-aarch64"
> > + elif [ "$(uname -m)" = "s390x" ]; then
> > + qemu="qemu-system-s390x"
> > + elif [ "$(uname -m)" = "ppc64le" ]; then
> > + qemu="qemu-system-ppc64"
> > + else
> > + qemu="qemu-system-$(uname -m)"
> > + fi
> > +
> > + if ! which -s "$qemu"; then
> > + skip "$qemu not found"
> > + fi
> > +
> > + if [ ! -r /dev/kvm ] || [ ! -w /dev/kvm ]; then
> > + skip "/dev/kvm not accessible"
> > + fi
> > +
> > + if ! perf kvm stat record -a sleep 0.01 >/dev/null 2>&1; then
> > + skip "No permission to record kvm events"
> > + fi
> > +
> > + echo "Starting $qemu..."
> > + # Start qemu in background, detached, with pidfile
> > + # We use -display none -daemonize and a monitor to keep it alive/controllable if needed
> > + # We don't need a real kernel, just KVM active.
> > + if ! $qemu -enable-kvm -display none -daemonize -pidfile "${qemu_pid_file}" -monitor none; then
>
> What is running in the guest?
Nothing. As no kernel or storage image were provided the guest should
be waiting at the bios similar to if you booted a PC with no storage
in it. I just wanted something quick and dirty to give the basic perf
kvm command a simple work out for the sake of testing coverage.
Thanks,
Ian
> Thanks,
> Namhyung
>
>
> > + echo "Failed to start qemu"
> > + err=1
> > + return
> > + fi
> > +
> > + # Wait a bit for qemu to start
> > + sleep 1
> > + qemu_pid=$(cat "${qemu_pid_file}")
> > +
> > + if ! kill -0 "${qemu_pid}" 2>/dev/null; then
> > + echo "Qemu process failed to stay alive"
> > + err=1
> > + return
> > + fi
> > +}
> > +
> > +setup_qemu
> > +if [ $err -eq 0 ]; then
> > + test_kvm_stat
> > + test_kvm_record_report
> > + test_kvm_buildid_list
> > +fi
> > +
> > +cleanup
> > +exit $err
> > --
> > 2.52.0.rc2.455.g230fcf2819-goog
> >
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