This series implements feature detection of hardware virtualization on Linux and macOS; the latter being my primary use case.
This yields approximately a 6x improvement using HVF on M3 Pro.
Signed-off-by: Tamir Duberstein tamird@gmail.com --- Tamir Duberstein (2): kunit: add fallback for os.sched_getaffinity kunit: enable hardware acceleration when available
tools/testing/kunit/kunit.py | 11 ++++++++++- tools/testing/kunit/kunit_kernel.py | 26 +++++++++++++++++++++++++- tools/testing/kunit/qemu_configs/arm64.py | 2 +- 3 files changed, 36 insertions(+), 3 deletions(-) --- base-commit: ae90f6a6170d7a7a1aa4fddf664fbd093e3023bc change-id: 20241025-kunit-qemu-accel-macos-2840e4c2def5
Best regards,
Python 3.13 added os.process_cpu_count as a cross-platform alternative for the Linux-only os.sched_getaffinity. Use it when it's available and provide a fallback when it's not.
This allows kunit to run on macOS.
Signed-off-by: Tamir Duberstein tamird@gmail.com --- tools/testing/kunit/kunit.py | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/tools/testing/kunit/kunit.py b/tools/testing/kunit/kunit.py index bc74088c458aee20b1a21fdeb9f3cb01ab20fec4..3a8cbb868ac559f68d047e38be92f7c64a3314ea 100755 --- a/tools/testing/kunit/kunit.py +++ b/tools/testing/kunit/kunit.py @@ -303,7 +303,16 @@ def massage_argv(argv: Sequence[str]) -> Sequence[str]: return list(map(massage_arg, argv))
def get_default_jobs() -> int: - return len(os.sched_getaffinity(0)) + if sys.version_info >= (3, 13): + if (ncpu := os.process_cpu_count()) is not None: + return ncpu + raise RuntimeError("os.process_cpu_count() returned None") + # See https://github.com/python/cpython/blob/b61fece/Lib/os.py#L1175-L1186. + if sys.platform != "darwin": + return len(os.sched_getaffinity(0)) + if (ncpu := os.cpu_count()) is not None: + return ncpu + raise RuntimeError("os.cpu_count() returned None")
def add_common_opts(parser: argparse.ArgumentParser) -> None: parser.add_argument('--build_dir',
Use KVM or HVF if supported by the QEMU binary and available on the system.
This produces a nice improvement on my Apple M3 Pro running macOS 14.7:
Before: ./tools/testing/kunit/kunit.py exec --arch arm64 [HH:MM:SS] Elapsed time: 10.145s
After: ./tools/testing/kunit/kunit.py exec --arch arm64 [HH:MM:SS] Elapsed time: 1.773s
Signed-off-by: Tamir Duberstein tamird@gmail.com --- tools/testing/kunit/kunit_kernel.py | 26 +++++++++++++++++++++++++- tools/testing/kunit/qemu_configs/arm64.py | 2 +- 2 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py index 61931c4926fd6645f2c62dd13f9842a432ec4167..10cacf5a3c443bacd6c074647e4bddfc31599cf8 100644 --- a/tools/testing/kunit/kunit_kernel.py +++ b/tools/testing/kunit/kunit_kernel.py @@ -116,7 +116,8 @@ class LinuxSourceTreeOperationsQemu(LinuxSourceTreeOperations):
def start(self, params: List[str], build_dir: str) -> subprocess.Popen: kernel_path = os.path.join(build_dir, self._kernel_path) - qemu_command = ['qemu-system-' + self._qemu_arch, + qemu_binary = 'qemu-system-' + self._qemu_arch + qemu_command = [qemu_binary, '-nodefaults', '-m', '1024', '-kernel', kernel_path, @@ -124,6 +125,29 @@ class LinuxSourceTreeOperationsQemu(LinuxSourceTreeOperations): '-no-reboot', '-nographic', '-serial', self._serial] + self._extra_qemu_params + accelerators = { + line.strip() + for line in subprocess.check_output([qemu_binary, "-accel", "help"], text=True).splitlines() + if line and line.islower() + } + if 'kvm' in accelerators: + try: + with open('/dev/kvm', 'rb+'): + qemu_command.extend(['-accel', 'kvm']) + except OSError as e: + print(e) + elif 'hvf' in accelerators: + try: + for line in subprocess.check_output(['sysctl', 'kern.hv_support'], text=True).splitlines(): + if not line: + continue + key, value = line.split(':') + if key == 'kern.hv_support' and bool(value): + qemu_command.extend(['-accel', 'hvf']) + break + except subprocess.CalledProcessError as e: + print(e) + # Note: shlex.join() does what we want, but requires python 3.8+. print('Running tests with:\n$', ' '.join(shlex.quote(arg) for arg in qemu_command)) return subprocess.Popen(qemu_command, diff --git a/tools/testing/kunit/qemu_configs/arm64.py b/tools/testing/kunit/qemu_configs/arm64.py index d3ff27024755411441f910799be30399295c9541..5c44d3a87e6dd2cd6b086138186a277a1473585b 100644 --- a/tools/testing/kunit/qemu_configs/arm64.py +++ b/tools/testing/kunit/qemu_configs/arm64.py @@ -9,4 +9,4 @@ CONFIG_SERIAL_AMBA_PL011_CONSOLE=y''', qemu_arch='aarch64', kernel_path='arch/arm64/boot/Image.gz', kernel_command_line='console=ttyAMA0', - extra_qemu_params=['-machine', 'virt', '-cpu', 'max,pauth-impdef=on']) + extra_qemu_params=['-machine', 'virt', '-cpu', 'max'])
On Fri, Oct 25, 2024 at 05:03:54PM -0400, Tamir Duberstein wrote:
QEMU supports falling back if one accelerator is not available, if you specify multiple like -accel kvm:tcg. Couldn't you rely on that rather than re-implementing the availability checks here?
On Fri, Nov 1, 2024, 09:52 Alyssa Ross hi@alyssa.is wrote:
Have you ever used that? Here's what I get when I try:
tamird@Tamirs-MacBook-Pro linux % tools/testing/kunit/kunit.py run --arch arm64 --make_options LLVM=1 --raw_output=all [10:45:03] Configuring KUnit Kernel ... [10:45:03] Building KUnit Kernel ... Populating config with: $ make ARCH=arm64 O=.kunit olddefconfig LLVM=1 Building with: $ make all compile_commands.json ARCH=arm64 O=.kunit --jobs=12 LLVM=1 [10:45:07] Starting KUnit Kernel (1/1)... Running tests with: $ qemu-system-aarch64 -nodefaults -m 1024 -kernel .kunit/arch/arm64/boot/Image.gz -append 'kunit.enable=1 console=ttyAMA0 kunit_shutdown=reboot' -no-reboot -nographic -serial stdio -accel kvm:tcg -machine virt -cpu max qemu-system-aarch64: -accel kvm:tcg: invalid accelerator kvm:tcg
The same thing happens with hvf:kvm:tcg or just hvf:tcg.
I also can't find this in the documentation. Tamir
On 2024-11-01 10:49:36-0400, Tamir Duberstein wrote:
That syntax is for -machine accel=hvf:kvm:tcg. But you can also specify -accel multiple times.
I also can't find this in the documentation.
-accel name[,prop=value[,...]] This is used to enable an accelerator. [..] If there is more than one accelerator specified, the next one is used if the previous one fails to initialize.
-machine [type=]name[,prop=value[,...]] Supported machine properties are:
accel=accels1[:accels2[:...]] [..] If there is more than one accelerator specified, the next one is used if the previous one fails to initialize.
Thomas
On Fri, Nov 1, 2024 at 11:23 AM Thomas Weißschuh thomas@t-8ch.de wrote:
Nice, thank you. These details seem to appear only in the docs[0] and not in the output of `--help`. I'll make that change in v2.
Link: https://www.qemu.org/docs/master/system/invocation.html [0]
Tamir
linux-kselftest-mirror@lists.linaro.org
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Alyssa Ross -
Tamir Duberstein -
Thomas Weißschuh