Enum sc_sysinfo::ExecutionLimit

pub enum ExecutionLimit {
    MaxDuration(Duration),
    MaxIterations(usize),
    Both {
        max_iterations: usize,
        max_duration: Duration,
    },
}

Limit the execution time of a benchmark.

Variants

MaxDuration(Duration)

Limit by the maximal duration.

MaxIterations(usize)

Limit by the maximal number of iterations.

Both

Fields

max_iterations: usize

max_duration: Duration

Limit by the maximal duration and maximal number of iterations.

Implementations

impl ExecutionLimit

pub fn from_secs_f32(secs: f32) -> Self

Creates a new execution limit with the passed seconds as duration limit.

pub fn max_duration(&self) -> Duration

Returns the duration limit or MAX if none is present.

Examples found in repository

src/sysinfo.rs (line 256)

pub fn benchmark_cpu(limit: ExecutionLimit) -> Throughput {
	// In general the results of this benchmark are somewhat sensitive to how much
	// data we hash at the time. The smaller this is the *less* B/s we can hash,
	// the bigger this is the *more* B/s we can hash, up until a certain point
	// where we can achieve roughly ~100% of what the hasher can do. If we'd plot
	// this on a graph with the number of bytes we want to hash on the X axis
	// and the speed in B/s on the Y axis then we'd essentially see it grow
	// logarithmically.
	//
	// In practice however we might not always have enough data to hit the maximum
	// possible speed that the hasher can achieve, so the size set here should be
	// picked in such a way as to still measure how fast the hasher is at hashing,
	// but without hitting its theoretical maximum speed.
	const SIZE: usize = 32 * 1024;

	let mut buffer = Vec::new();
	buffer.resize(SIZE, 0x66);
	let mut hash = Default::default();

	let run = || -> Result<(), ()> {
		clobber_slice(&mut buffer);
		hash = sp_core::hashing::blake2_256(&buffer);
		clobber_slice(&mut hash);

		Ok(())
	};

	benchmark("CPU score", SIZE, limit.max_iterations(), limit.max_duration(), run)
		.expect("benchmark cannot fail; qed")
}

/// A default [`ExecutionLimit`] that can be used to call [`benchmark_memory`].
pub const DEFAULT_MEMORY_EXECUTION_LIMIT: ExecutionLimit =
	ExecutionLimit::Both { max_iterations: 32, max_duration: Duration::from_millis(100) };

// This benchmarks the effective `memcpy` memory bandwidth available in bytes per second.
//
// It doesn't technically measure the absolute maximum memory bandwidth available,
// but that's fine, because real code most of the time isn't optimized to take
// advantage of the full memory bandwidth either.
pub fn benchmark_memory(limit: ExecutionLimit) -> Throughput {
	// Ideally this should be at least as big as the CPU's L3 cache,
	// and it should be big enough so that the `memcpy` takes enough
	// time to be actually measurable.
	//
	// As long as it's big enough increasing it further won't change
	// the benchmark's results.
	const SIZE: usize = 64 * 1024 * 1024;

	let mut src = Vec::new();
	let mut dst = Vec::new();

	// Prefault the pages; we want to measure the memory bandwidth,
	// not how fast the kernel can supply us with fresh memory pages.
	src.resize(SIZE, 0x66);
	dst.resize(SIZE, 0x77);

	let run = || -> Result<(), ()> {
		clobber_slice(&mut src);
		clobber_slice(&mut dst);

		// SAFETY: Both vectors are of the same type and of the same size,
		//         so copying data between them is safe.
		unsafe {
			// We use `memcpy` directly here since `copy_from_slice` isn't actually
			// guaranteed to be turned into a `memcpy`.
			libc::memcpy(dst.as_mut_ptr().cast(), src.as_ptr().cast(), SIZE);
		}

		clobber_slice(&mut dst);
		clobber_slice(&mut src);

		Ok(())
	};

	benchmark("memory score", SIZE, limit.max_iterations(), limit.max_duration(), run)
		.expect("benchmark cannot fail; qed")
}

struct TemporaryFile {
	fp: Option<File>,
	path: PathBuf,
}

impl Drop for TemporaryFile {
	fn drop(&mut self) {
		let _ = self.fp.take();

		// Remove the file.
		//
		// This has to be done *after* the benchmark,
		// otherwise it changes the results as the data
		// doesn't actually get properly flushed to the disk,
		// since the file's not there anymore.
		if let Err(error) = std::fs::remove_file(&self.path) {
			log::warn!("Failed to remove the file used for the disk benchmark: {}", error);
		}
	}
}

impl Deref for TemporaryFile {
	type Target = File;
	fn deref(&self) -> &Self::Target {
		self.fp.as_ref().expect("`fp` is None only during `drop`")
	}
}

impl DerefMut for TemporaryFile {
	fn deref_mut(&mut self) -> &mut Self::Target {
		self.fp.as_mut().expect("`fp` is None only during `drop`")
	}
}

fn rng() -> rand_pcg::Pcg64 {
	rand_pcg::Pcg64::new(0xcafef00dd15ea5e5, 0xa02bdbf7bb3c0a7ac28fa16a64abf96)
}

fn random_data(size: usize) -> Vec<u8> {
	let mut buffer = Vec::new();
	buffer.resize(size, 0);
	rng().fill(&mut buffer[..]);
	buffer
}

/// A default [`ExecutionLimit`] that can be used to call [`benchmark_disk_sequential_writes`]
/// and [`benchmark_disk_random_writes`].
pub const DEFAULT_DISK_EXECUTION_LIMIT: ExecutionLimit =
	ExecutionLimit::Both { max_iterations: 32, max_duration: Duration::from_millis(300) };

pub fn benchmark_disk_sequential_writes(
	limit: ExecutionLimit,
	directory: &Path,
) -> Result<Throughput, String> {
	const SIZE: usize = 64 * 1024 * 1024;

	let buffer = random_data(SIZE);
	let path = directory.join(".disk_bench_seq_wr.tmp");

	let fp =
		File::create(&path).map_err(|error| format!("failed to create a test file: {}", error))?;

	let mut fp = TemporaryFile { fp: Some(fp), path };

	fp.sync_all()
		.map_err(|error| format!("failed to fsync the test file: {}", error))?;

	let run = || {
		// Just dump everything to the disk in one go.
		fp.write_all(&buffer)
			.map_err(|error| format!("failed to write to the test file: {}", error))?;

		// And then make sure it was actually written to disk.
		fp.sync_all()
			.map_err(|error| format!("failed to fsync the test file: {}", error))?;

		// Rewind to the beginning for the next iteration of the benchmark.
		fp.seek(SeekFrom::Start(0))
			.map_err(|error| format!("failed to seek to the start of the test file: {}", error))?;

		Ok(())
	};

	benchmark(
		"disk sequential write score",
		SIZE,
		limit.max_iterations(),
		limit.max_duration(),
		run,
	)
}

pub fn benchmark_disk_random_writes(
	limit: ExecutionLimit,
	directory: &Path,
) -> Result<Throughput, String> {
	const SIZE: usize = 64 * 1024 * 1024;

	let buffer = random_data(SIZE);
	let path = directory.join(".disk_bench_rand_wr.tmp");

	let fp =
		File::create(&path).map_err(|error| format!("failed to create a test file: {}", error))?;

	let mut fp = TemporaryFile { fp: Some(fp), path };

	// Since we want to test random writes we need an existing file
	// through which we can seek, so here we just populate it with some data.
	fp.write_all(&buffer)
		.map_err(|error| format!("failed to write to the test file: {}", error))?;

	fp.sync_all()
		.map_err(|error| format!("failed to fsync the test file: {}", error))?;

	// Generate a list of random positions at which we'll issue writes.
	let mut positions = Vec::with_capacity(SIZE / 4096);
	{
		let mut position = 0;
		while position < SIZE {
			positions.push(position);
			position += 4096;
		}
	}

	positions.shuffle(&mut rng());

	let run = || {
		for &position in &positions {
			fp.seek(SeekFrom::Start(position as u64))
				.map_err(|error| format!("failed to seek in the test file: {}", error))?;

			// Here we deliberately only write half of the chunk since we don't
			// want the OS' disk scheduler to coalesce our writes into one single
			// sequential write.
			//
			// Also the chunk's size is deliberately exactly half of a modern disk's
			// sector size to trigger an RMW cycle.
			let chunk = &buffer[position..position + 2048];
			fp.write_all(&chunk)
				.map_err(|error| format!("failed to write to the test file: {}", error))?;
		}

		fp.sync_all()
			.map_err(|error| format!("failed to fsync the test file: {}", error))?;

		Ok(())
	};

	// We only wrote half of the bytes hence `SIZE / 2`.
	benchmark(
		"disk random write score",
		SIZE / 2,
		limit.max_iterations(),
		limit.max_duration(),
		run,
	)
}

/// Benchmarks the verification speed of sr25519 signatures.
///
/// Returns the throughput in B/s by convention.
/// The values are rather small (0.4-0.8) so it is advised to convert them into KB/s.
pub fn benchmark_sr25519_verify(limit: ExecutionLimit) -> Throughput {
	const INPUT_SIZE: usize = 32;
	const ITERATION_SIZE: usize = 2048;
	let pair = sr25519::Pair::from_string("//Alice", None).unwrap();

	let mut rng = rng();
	let mut msgs = Vec::new();
	let mut sigs = Vec::new();

	for _ in 0..ITERATION_SIZE {
		let mut msg = vec![0u8; INPUT_SIZE];
		rng.fill_bytes(&mut msg[..]);

		sigs.push(pair.sign(&msg));
		msgs.push(msg);
	}

	let run = || -> Result<(), String> {
		for (sig, msg) in sigs.iter().zip(msgs.iter()) {
			let mut ok = sr25519_verify(&sig, &msg[..], &pair.public());
			clobber_value(&mut ok);
		}
		Ok(())
	};
	benchmark(
		"sr25519 verification score",
		INPUT_SIZE * ITERATION_SIZE,
		limit.max_iterations(),
		limit.max_duration(),
		run,
	)
	.expect("sr25519 verification cannot fail; qed")
}

pub fn max_iterations(&self) -> usize

Returns the iterations limit or MAX if none is present.

Examples found in repository

src/sysinfo.rs (line 256)

pub fn benchmark_cpu(limit: ExecutionLimit) -> Throughput {
	// In general the results of this benchmark are somewhat sensitive to how much
	// data we hash at the time. The smaller this is the *less* B/s we can hash,
	// the bigger this is the *more* B/s we can hash, up until a certain point
	// where we can achieve roughly ~100% of what the hasher can do. If we'd plot
	// this on a graph with the number of bytes we want to hash on the X axis
	// and the speed in B/s on the Y axis then we'd essentially see it grow
	// logarithmically.
	//
	// In practice however we might not always have enough data to hit the maximum
	// possible speed that the hasher can achieve, so the size set here should be
	// picked in such a way as to still measure how fast the hasher is at hashing,
	// but without hitting its theoretical maximum speed.
	const SIZE: usize = 32 * 1024;

	let mut buffer = Vec::new();
	buffer.resize(SIZE, 0x66);
	let mut hash = Default::default();

	let run = || -> Result<(), ()> {
		clobber_slice(&mut buffer);
		hash = sp_core::hashing::blake2_256(&buffer);
		clobber_slice(&mut hash);

		Ok(())
	};

	benchmark("CPU score", SIZE, limit.max_iterations(), limit.max_duration(), run)
		.expect("benchmark cannot fail; qed")
}

/// A default [`ExecutionLimit`] that can be used to call [`benchmark_memory`].
pub const DEFAULT_MEMORY_EXECUTION_LIMIT: ExecutionLimit =
	ExecutionLimit::Both { max_iterations: 32, max_duration: Duration::from_millis(100) };

// This benchmarks the effective `memcpy` memory bandwidth available in bytes per second.
//
// It doesn't technically measure the absolute maximum memory bandwidth available,
// but that's fine, because real code most of the time isn't optimized to take
// advantage of the full memory bandwidth either.
pub fn benchmark_memory(limit: ExecutionLimit) -> Throughput {
	// Ideally this should be at least as big as the CPU's L3 cache,
	// and it should be big enough so that the `memcpy` takes enough
	// time to be actually measurable.
	//
	// As long as it's big enough increasing it further won't change
	// the benchmark's results.
	const SIZE: usize = 64 * 1024 * 1024;

	let mut src = Vec::new();
	let mut dst = Vec::new();

	// Prefault the pages; we want to measure the memory bandwidth,
	// not how fast the kernel can supply us with fresh memory pages.
	src.resize(SIZE, 0x66);
	dst.resize(SIZE, 0x77);

	let run = || -> Result<(), ()> {
		clobber_slice(&mut src);
		clobber_slice(&mut dst);

		// SAFETY: Both vectors are of the same type and of the same size,
		//         so copying data between them is safe.
		unsafe {
			// We use `memcpy` directly here since `copy_from_slice` isn't actually
			// guaranteed to be turned into a `memcpy`.
			libc::memcpy(dst.as_mut_ptr().cast(), src.as_ptr().cast(), SIZE);
		}

		clobber_slice(&mut dst);
		clobber_slice(&mut src);

		Ok(())
	};

	benchmark("memory score", SIZE, limit.max_iterations(), limit.max_duration(), run)
		.expect("benchmark cannot fail; qed")
}

struct TemporaryFile {
	fp: Option<File>,
	path: PathBuf,
}

impl Drop for TemporaryFile {
	fn drop(&mut self) {
		let _ = self.fp.take();

		// Remove the file.
		//
		// This has to be done *after* the benchmark,
		// otherwise it changes the results as the data
		// doesn't actually get properly flushed to the disk,
		// since the file's not there anymore.
		if let Err(error) = std::fs::remove_file(&self.path) {
			log::warn!("Failed to remove the file used for the disk benchmark: {}", error);
		}
	}
}

impl Deref for TemporaryFile {
	type Target = File;
	fn deref(&self) -> &Self::Target {
		self.fp.as_ref().expect("`fp` is None only during `drop`")
	}
}

impl DerefMut for TemporaryFile {
	fn deref_mut(&mut self) -> &mut Self::Target {
		self.fp.as_mut().expect("`fp` is None only during `drop`")
	}
}

fn rng() -> rand_pcg::Pcg64 {
	rand_pcg::Pcg64::new(0xcafef00dd15ea5e5, 0xa02bdbf7bb3c0a7ac28fa16a64abf96)
}

fn random_data(size: usize) -> Vec<u8> {
	let mut buffer = Vec::new();
	buffer.resize(size, 0);
	rng().fill(&mut buffer[..]);
	buffer
}

/// A default [`ExecutionLimit`] that can be used to call [`benchmark_disk_sequential_writes`]
/// and [`benchmark_disk_random_writes`].
pub const DEFAULT_DISK_EXECUTION_LIMIT: ExecutionLimit =
	ExecutionLimit::Both { max_iterations: 32, max_duration: Duration::from_millis(300) };

pub fn benchmark_disk_sequential_writes(
	limit: ExecutionLimit,
	directory: &Path,
) -> Result<Throughput, String> {
	const SIZE: usize = 64 * 1024 * 1024;

	let buffer = random_data(SIZE);
	let path = directory.join(".disk_bench_seq_wr.tmp");

	let fp =
		File::create(&path).map_err(|error| format!("failed to create a test file: {}", error))?;

	let mut fp = TemporaryFile { fp: Some(fp), path };

	fp.sync_all()
		.map_err(|error| format!("failed to fsync the test file: {}", error))?;

	let run = || {
		// Just dump everything to the disk in one go.
		fp.write_all(&buffer)
			.map_err(|error| format!("failed to write to the test file: {}", error))?;

		// And then make sure it was actually written to disk.
		fp.sync_all()
			.map_err(|error| format!("failed to fsync the test file: {}", error))?;

		// Rewind to the beginning for the next iteration of the benchmark.
		fp.seek(SeekFrom::Start(0))
			.map_err(|error| format!("failed to seek to the start of the test file: {}", error))?;

		Ok(())
	};

	benchmark(
		"disk sequential write score",
		SIZE,
		limit.max_iterations(),
		limit.max_duration(),
		run,
	)
}

pub fn benchmark_disk_random_writes(
	limit: ExecutionLimit,
	directory: &Path,
) -> Result<Throughput, String> {
	const SIZE: usize = 64 * 1024 * 1024;

	let buffer = random_data(SIZE);
	let path = directory.join(".disk_bench_rand_wr.tmp");

	let fp =
		File::create(&path).map_err(|error| format!("failed to create a test file: {}", error))?;

	let mut fp = TemporaryFile { fp: Some(fp), path };

	// Since we want to test random writes we need an existing file
	// through which we can seek, so here we just populate it with some data.
	fp.write_all(&buffer)
		.map_err(|error| format!("failed to write to the test file: {}", error))?;

	fp.sync_all()
		.map_err(|error| format!("failed to fsync the test file: {}", error))?;

	// Generate a list of random positions at which we'll issue writes.
	let mut positions = Vec::with_capacity(SIZE / 4096);
	{
		let mut position = 0;
		while position < SIZE {
			positions.push(position);
			position += 4096;
		}
	}

	positions.shuffle(&mut rng());

	let run = || {
		for &position in &positions {
			fp.seek(SeekFrom::Start(position as u64))
				.map_err(|error| format!("failed to seek in the test file: {}", error))?;

			// Here we deliberately only write half of the chunk since we don't
			// want the OS' disk scheduler to coalesce our writes into one single
			// sequential write.
			//
			// Also the chunk's size is deliberately exactly half of a modern disk's
			// sector size to trigger an RMW cycle.
			let chunk = &buffer[position..position + 2048];
			fp.write_all(&chunk)
				.map_err(|error| format!("failed to write to the test file: {}", error))?;
		}

		fp.sync_all()
			.map_err(|error| format!("failed to fsync the test file: {}", error))?;

		Ok(())
	};

	// We only wrote half of the bytes hence `SIZE / 2`.
	benchmark(
		"disk random write score",
		SIZE / 2,
		limit.max_iterations(),
		limit.max_duration(),
		run,
	)
}

/// Benchmarks the verification speed of sr25519 signatures.
///
/// Returns the throughput in B/s by convention.
/// The values are rather small (0.4-0.8) so it is advised to convert them into KB/s.
pub fn benchmark_sr25519_verify(limit: ExecutionLimit) -> Throughput {
	const INPUT_SIZE: usize = 32;
	const ITERATION_SIZE: usize = 2048;
	let pair = sr25519::Pair::from_string("//Alice", None).unwrap();

	let mut rng = rng();
	let mut msgs = Vec::new();
	let mut sigs = Vec::new();

	for _ in 0..ITERATION_SIZE {
		let mut msg = vec![0u8; INPUT_SIZE];
		rng.fill_bytes(&mut msg[..]);

		sigs.push(pair.sign(&msg));
		msgs.push(msg);
	}

	let run = || -> Result<(), String> {
		for (sig, msg) in sigs.iter().zip(msgs.iter()) {
			let mut ok = sr25519_verify(&sig, &msg[..], &pair.public());
			clobber_value(&mut ok);
		}
		Ok(())
	};
	benchmark(
		"sr25519 verification score",
		INPUT_SIZE * ITERATION_SIZE,
		limit.max_iterations(),
		limit.max_duration(),
		run,
	)
	.expect("sr25519 verification cannot fail; qed")
}