azat’s gists

azat / test-syscalls-musl-static.sh

Last active July 12, 2024 12:37

How many syscalls on Linux can you have?

	$ lscpu -J \| jq '.lscpu.[] \| select(.field == "Model name:").data' -r
	AMD Ryzen Threadripper PRO 5975WX 32-Cores
	$ musl-clang -static -O3 -o test-syscalls test-syscalls.cpp
	$ ldd test-syscalls
	not a dynamic executable
	$ ./test-syscalls
	gettid: 48735.848us, 20518777.061 cps, 48.736 ns per call
	clock_gettime (VDSO): 20660.516us, 48401501.686 cps, 20.661 ns per call
	nothing_indirect_call: 0.020us, 50000000000000.000 cps, 0.000 ns per call
	nothing: 0.020us, 50000000000000.000 cps, 0.000 ns per call

azat / test-clocks.cpp

Created January 26, 2024 08:26

Test clocks (clock_gettime and RDTSC)

	#include <cstdint>
	#include <ctime>
	#include <cerrno>
	#include <iostream>
	#include <utility>

	uint64_t now_ns(clockid_t clock)
	{
	struct timespec ts;
	clock_gettime(clock, &ts);

azat / test-threads-v2.cpp

Last active January 25, 2024 21:35

test pthread_create

	#include <cstdint>
	#include <ctime>
	#include <iostream>
	#include <sys/types.h>
	#include <thread>
	#include <list>

	uint64_t now_ns()
	{
	struct timespec ts;

azat / lockstat.py

Created January 17, 2024 16:14

pthread lock statistics with eBPF

	#!/usr/bin/env python

	# Based on https://github.com/goldshtn/linux-tracing-workshop
	# Based on https://gist.github.com/SaveTheRbtz/807be09f73d13b80e429d45bd1707e00

	"""
	The MIT License (MIT)

	Copyright (c) 2017 Sasha Goldshtein
	Copyright (c) 2018 Alexey Ivanov

azat / cpu-cache-effects.c

Created December 20, 2023 19:13

	#include <bits/time.h>
	#include <stdint.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <sys/types.h>
	#include <time.h>

	// https://igoro.com/archive/gallery-of-processor-cache-effects/

	u_int64_t now_ns()

azat / bench-jemalloc-cache-oblivious.c

Last active December 20, 2023 19:33

Answers the question "Does cache oblivious in jemalloc still make sense?" - Yes

	#include <bits/time.h>
	#include <stdint.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <sys/types.h>
	#include <time.h>

	// Answers the question "Does cache oblivious in jemalloc still make sense?"
	// The short answer is "Yes"!
	//

azat / bench-madvise.py

Last active December 16, 2023 17:33

MADV_FREE vs MADV_DONTNEED benchmark

	#!/usr/bin/env python3

	import mmap
	import time

	NUMBER_VMAS = 10000
	VMA_SIZE = 1<<20
	buffer = b'0' * VMA_SIZE

	def make_vma():

azat / madvise.py

Last active December 16, 2023 17:34

MADV_FREE vs MADV_DONTNEED: how the memory is accounted

	#!/usr/bin/env python3

	# systemd-run --user --unit test-madvise ./test.py
	# journalctl -u -r

	import mmap
	import resource
	import os

	def get_cgroup_id():

azat / libevent-bswap.c

Created November 26, 2023 20:54

	#include <limits.h>
	#include <stddef.h>
	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>

	int main(int argc, char **argv)
	{
	const char * arg = argv[1];
	uint64_t in_host = strtoll(arg, NULL, 16);

azat / flamegraph.txt

Created November 25, 2023 06:55

void boost::context::detail::fiber_entry<boost::context::detail::fiber_record<boost::context::fiber, FiberStack&, Fiber::RoutineImpl<DB::AsyncTaskExecutor::Routine>>>(boost::context::detail::transfer_t);DB::AsyncTaskExecutor::Routine::operator()(std::__1::function<void ()>);DB::RemoteQueryExecutorReadContext::Task::run(std::__1::function<void (int, Poco::Timespan, DB::AsyncEventTimeoutType, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int)>, std::__1::function<void ()>);DB::MultiplexedConnections::receivePacketUnlocked(std::__1::function<void (int, Poco::Timespan, DB::AsyncEventTimeoutType, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int)>);DB::Connection::receivePacket();DB::Connection::receiveDataImpl(DB::NativeReader&);DB::NativeReader::read();DB::IDataType::createColumn(DB::ISerialization const&) const;DB::DataTypeNumberBase<unsigned long>::createColumn() const;operator new(unsigned long);mal

Azat Khuzhin azat