ladybird/Kernel/PerformanceManager.h
Jean-Baptiste Boric 0286160b62 Kernel: Add syscall performance event type
This allows tracing the syscalls made by a thread through the kernel's
performance event framework, which is similar in principle to strace.

Currently, this merely logs a stack backtrace to the current thread's
performance event buffer whenever a syscall is made, if profiling is
enabled. Future improvements could include tracing the arguments and
the return value, for example.
2021-08-10 21:55:48 +02:00

153 lines
6.0 KiB
C++

/*
* Copyright (c) 2021, Brian Gianforcaro <bgianf@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <Kernel/PerformanceEventBuffer.h>
#include <Kernel/Process.h>
#include <Kernel/Thread.h>
namespace Kernel {
class PerformanceManager {
public:
inline static void add_process_created_event(Process& process)
{
if (g_profiling_all_threads) {
VERIFY(g_global_perf_events);
g_global_perf_events->add_process(process, ProcessEventType::Create);
}
}
inline static void add_process_exec_event(Process& process)
{
if (auto* event_buffer = process.current_perf_events_buffer()) {
event_buffer->add_process(process, ProcessEventType::Exec);
}
}
inline static void add_process_exit_event(Process& process)
{
if (g_profiling_all_threads) {
VERIFY(g_global_perf_events);
[[maybe_unused]] auto rc = g_global_perf_events->append_with_ip_and_bp(
process.pid(), 0, 0, 0, PERF_EVENT_PROCESS_EXIT, 0, 0, 0, nullptr);
}
}
inline static void add_thread_created_event(Thread& thread)
{
if (thread.is_profiling_suppressed())
return;
if (auto* event_buffer = thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto rc = event_buffer->append(PERF_EVENT_THREAD_CREATE, thread.tid().value(), 0, nullptr, &thread);
}
}
inline static void add_thread_exit_event(Thread& thread)
{
// As an exception this doesn't check whether profiling is suppressed for
// the thread so we can record the thread_exit event anyway.
if (auto* event_buffer = thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto rc = event_buffer->append(PERF_EVENT_THREAD_EXIT, thread.tid().value(), 0, nullptr, &thread);
}
}
inline static void add_cpu_sample_event(Thread& current_thread, const RegisterState& regs, u32 lost_time)
{
if (current_thread.is_profiling_suppressed())
return;
if (auto* event_buffer = current_thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto rc = event_buffer->append_with_ip_and_bp(
current_thread.pid(), current_thread.tid(),
regs.ip(), regs.bp(), PERF_EVENT_SAMPLE, lost_time, 0, 0, nullptr);
}
}
inline static void add_mmap_perf_event(Process& current_process, Memory::Region const& region)
{
if (auto* event_buffer = current_process.current_perf_events_buffer()) {
[[maybe_unused]] auto res = event_buffer->append(PERF_EVENT_MMAP, region.vaddr().get(), region.size(), region.name());
}
}
inline static void add_unmap_perf_event(Process& current_process, Memory::VirtualRange const& region)
{
if (auto* event_buffer = current_process.current_perf_events_buffer()) {
[[maybe_unused]] auto res = event_buffer->append(PERF_EVENT_MUNMAP, region.base().get(), region.size(), nullptr);
}
}
inline static void add_context_switch_perf_event(Thread& current_thread, Thread& next_thread)
{
if (current_thread.is_profiling_suppressed())
return;
if (auto* event_buffer = current_thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto res = event_buffer->append(PERF_EVENT_CONTEXT_SWITCH, next_thread.pid().value(), next_thread.tid().value(), nullptr);
}
}
inline static void add_kmalloc_perf_event(Thread& current_thread, size_t size, FlatPtr ptr)
{
if (current_thread.is_profiling_suppressed())
return;
if (auto* event_buffer = current_thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto res = event_buffer->append(PERF_EVENT_KMALLOC, size, ptr, nullptr);
}
}
inline static void add_kfree_perf_event(Thread& current_thread, size_t size, FlatPtr ptr)
{
if (current_thread.is_profiling_suppressed())
return;
if (auto* event_buffer = current_thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto res = event_buffer->append(PERF_EVENT_KFREE, size, ptr, nullptr);
}
}
inline static void add_page_fault_event(Thread& thread, const RegisterState& regs)
{
if (thread.is_profiling_suppressed())
return;
if (auto* event_buffer = thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto rc = event_buffer->append_with_ip_and_bp(
thread.pid(), thread.tid(),
regs.ip(), regs.bp(), PERF_EVENT_PAGE_FAULT, 0, 0, 0, nullptr);
}
}
inline static void add_syscall_event(Thread& thread, const RegisterState& regs)
{
if (thread.is_profiling_suppressed())
return;
if (auto* event_buffer = thread.process().current_perf_events_buffer()) {
[[maybe_unused]] auto rc = event_buffer->append_with_ip_and_bp(
thread.pid(), thread.tid(),
regs.ip(), regs.bp(), PERF_EVENT_SYSCALL, 0, 0, 0, nullptr);
}
}
inline static void timer_tick(RegisterState const& regs)
{
static Time last_wakeup;
auto now = kgettimeofday();
constexpr auto ideal_interval = Time::from_microseconds(1000'000 / OPTIMAL_PROFILE_TICKS_PER_SECOND_RATE);
auto expected_wakeup = last_wakeup + ideal_interval;
auto delay = (now > expected_wakeup) ? now - expected_wakeup : Time::from_microseconds(0);
last_wakeup = now;
auto current_thread = Thread::current();
// FIXME: We currently don't collect samples while idle.
// That will be an interesting mode to add in the future. :^)
if (!current_thread || current_thread == Processor::current().idle_thread())
return;
auto lost_samples = delay.to_microseconds() / ideal_interval.to_microseconds();
PerformanceManager::add_cpu_sample_event(*current_thread, regs, lost_samples);
}
};
}