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:
@@ -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:continuekey, value = line.split(':')if key == 'kern.hv_support' and bool(value):qemu_command.extend(['-accel', 'hvf'])breakexcept subprocess.CalledProcessError as e:print(e)
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:
On Fri, Oct 25, 2024 at 05:03:54PM -0400, Tamir Duberstein wrote:
@@ -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:continuekey, value = line.split(':')if key == 'kern.hv_support' and bool(value):qemu_command.extend(['-accel', 'hvf'])breakexcept subprocess.CalledProcessError as e:print(e)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?
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:
On Fri, Nov 1, 2024, 09:52 Alyssa Ross hi@alyssa.is wrote:
On Fri, Oct 25, 2024 at 05:03:54PM -0400, Tamir Duberstein wrote:
@@ -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:continuekey, value = line.split(':')if key == 'kern.hv_support' and bool(value):qemu_command.extend(['-accel', 'hvf'])breakexcept subprocess.CalledProcessError as e:print(e)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?
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.
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:
On 2024-11-01 10:49:36-0400, Tamir Duberstein wrote:
On Fri, Nov 1, 2024, 09:52 Alyssa Ross hi@alyssa.is wrote:
On Fri, Oct 25, 2024 at 05:03:54PM -0400, Tamir Duberstein wrote:
@@ -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:continuekey, value = line.split(':')if key == 'kern.hv_support' and bool(value):qemu_command.extend(['-accel', 'hvf'])breakexcept subprocess.CalledProcessError as e:print(e)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?
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.
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
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
-
Alyssa Ross -
Tamir Duberstein -
Thomas Weißschuh