From 00b31d1acf7490db17ffcb34882b625f103a4175 Mon Sep 17 00:00:00 2001
From: Kadin Sayani <kadin.sayani@canonical.com>
Date: Tue, 1 Oct 2024 09:57:49 -0600
Subject: [PATCH] tests/cpu-vm: Update VM CPU pinning tests to use
 `limits.cpu.pin_strategy` config option and corresponding API extension

Signed-off-by: Kadin Sayani <kadin.sayani@canonical.com>
---
 tests/cpu-vm | 58 +++++++++++++++++++++++++++++-----------------------
 1 file changed, 32 insertions(+), 26 deletions(-)

diff --git a/tests/cpu-vm b/tests/cpu-vm
index 145e21385..1cfc7b755 100755
--- a/tests/cpu-vm
+++ b/tests/cpu-vm
@@ -15,11 +15,10 @@ if ! hasNeededAPIExtension cpu_hotplug; then
   exit 0
 fi
 
-# required for "CPU auto pinning" feature check
-# as we don't have a separate API extension for it
-# and we rely on the debug output in the LXD daemon logs.
-snap set lxd daemon.debug=true
-systemctl restart snap.lxd.daemon.service
+if ! hasNeededAPIExtension limits_cpu_pin_strategy; then
+  echo "Skipping test as CPU pinning not supported on ${LXD_SNAP_CHANNEL}"
+  exit 0
+fi
 
 # Configure LXD
 lxc network create lxdbr0
@@ -52,8 +51,8 @@ fi
 
 lxc delete v0
 
-echo "==> Create ephemeral VM and boot"
-lxc launch "${IMAGE}" v1 --vm -s "${poolName}" --ephemeral
+echo "==> Create ephemeral VM with CPU pinning enabled and boot"
+lxc launch "${IMAGE}" v1 --vm -c limits.cpu.pin_strategy=auto -s "${poolName}" --ephemeral
 waitInstanceReady v1
 lxc info v1
 
@@ -86,24 +85,18 @@ done
 lxc config set v1 limits.cpu="${cpuCount}"
 [ "$(lxc exec v1 -- ls /sys/devices/system/cpu | grep -xEc 'cpu[[:digit:]]+')" -eq "${cpuCount}" ]
 
-# check that CPU affinity is automatically set if feature present
+echo "==> Check that CPU affinity is automatically set when limits.cpu.pin_strategy=auto"
 QEMU_PID=$(lxc info v1 | awk '/^PID:/ {print $2}')
-if journalctl --quiet --no-hostname --no-pager --boot=0 --unit=snap.lxd.daemon.service | grep "Scheduler: virtual-machine"; then
-  # Check that there are processes with pinning set
-  # It will be shown like this (for limits.cpu=2):
-  # pid 2894's current affinity list: 6
-  # pid 2895's current affinity list: 8
-  # pid 2897's current affinity list: 0-15
-  # pid 2898's current affinity list: 0-15
-  # pid 2899's current affinity list: 0-15
-  # 2894 and 2895 have affinity set, while others don't
-  PINNED_THREADS_NUM=$(taskset --cpu-list -a -p "${QEMU_PID}" | grep -cE ':\s+[0-9]+$')
-  [ "${PINNED_THREADS_NUM}" -ge "$(lxc config get v1 limits.cpu)" ]
-else
-  # check that there is no pinning set
-  ! taskset --cpu-list -a -p "${QEMU_PID}" | grep -E ':\s+[0-9]+$' || false
-  taskset --cpu-list -a -p "${QEMU_PID}" | grep "0-$((cpuCount-1))"
-fi
+# Check that there are processes with pinning set
+# It will be shown like this (for limits.cpu=2):
+# pid 2894's current affinity list: 6
+# pid 2895's current affinity list: 8
+# pid 2897's current affinity list: 0-15
+# pid 2898's current affinity list: 0-15
+# pid 2899's current affinity list: 0-15
+# 2894 and 2895 have affinity set, while others don't
+PINNED_THREADS_NUM=$(taskset --cpu-list -a -p "${QEMU_PID}" | grep -cE ':\s+[0-9]+$')
+[ "${PINNED_THREADS_NUM}" -ge "$(lxc config get v1 limits.cpu)" ]
 
 # Unset CPU limit
 lxc config unset v1 limits.cpu
@@ -111,10 +104,23 @@ lxc config unset v1 limits.cpu
 # Unsetting the limit should leave the VM with 1 CPU
 [ "$(lxc exec v1 -- ls /sys/devices/system/cpu | grep -xEc 'cpu[[:digit:]]+')" -eq "1" ]
 
-echo "==> Stopping and deleting ephemeral VM"
-# Stop VM and check its deleted.
+echo "==> Create ephemeral VM with CPU pinning disabled and boot"
+lxc launch "${IMAGE}" v2 --vm -c limits.cpu.pin_strategy=none -s "${poolName}" --ephemeral
+waitInstanceReady v2
+lxc info v2
+
+QEMU_PID=$(lxc info v2 | awk '/^PID:/ {print $2}')
+  
+echo "==> Check that there is no CPU pinning set"
+! taskset --cpu-list -a -p "${QEMU_PID}" | grep -E ':\s+[0-9]+$' || false
+taskset --cpu-list -a -p "${QEMU_PID}" | grep "0-$((cpuCount-1))"
+
+echo "==> Stopping and deleting ephemeral VMs"
+# Stop VMs and ensure deleted.
 lxc stop -f v1
 ! lxc info v1 || false
+lxc stop -f v2
+! lxc info v2 || false
 
 lxc profile device remove default eth0
 lxc profile unset default limits.kernel.nofile