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Kernel: Include the current instruction pointer in profile samples

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We were missing the innermost instruction pointer when sampling.
This makes the instruction-level profile info a lot cooler! :^)
This commit is contained in:
Andreas Kling 2020-04-11 20:39:27 +02:00
parent c106451daf
commit b7ff3b5ad1
4 changed files with 7 additions and 6 deletions
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5
Kernel/PerformanceEventBuffer.cpp
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@ -66,11 +66,12 @@ KResult PerformanceEventBuffer::append(int type, FlatPtr arg1, FlatPtr arg2)
FlatPtr ebp;
asm volatile("movl %%ebp, %%eax"
: "=a"(ebp));
//copy_from_user(&ebp, (FlatPtr*)current->get_register_dump_from_stack().ebp);
FlatPtr eip;
copy_from_user(&eip, (FlatPtr*)&Thread::current->get_register_dump_from_stack().eip);
Vector<FlatPtr> backtrace;
{
SmapDisabler disabler;
backtrace = Thread::current->raw_backtrace(ebp);
backtrace = Thread::current->raw_backtrace(ebp, eip);
}
event.stack_size = min(sizeof(event.stack) / sizeof(FlatPtr), static_cast<size_t>(backtrace.size()));
memcpy(event.stack, backtrace.data(), event.stack_size * sizeof(FlatPtr));

2
Kernel/Scheduler.cpp
View file

@ -603,7 +603,7 @@ void Scheduler::timer_tick(const RegisterState& regs)
if (Process::current->is_profiling()) {
SmapDisabler disabler;
auto backtrace = Thread::current->raw_backtrace(regs.ebp);
auto backtrace = Thread::current->raw_backtrace(regs.ebp, regs.eip);
auto& sample = Profiling::next_sample_slot();
sample.pid = Process::current->pid();
sample.tid = Thread::current->tid();

4
Kernel/Thread.cpp
View file

@ -846,13 +846,13 @@ String Thread::backtrace_impl() const
return builder.to_string();
}
Vector<FlatPtr> Thread::raw_backtrace(FlatPtr ebp) const
Vector<FlatPtr> Thread::raw_backtrace(FlatPtr ebp, FlatPtr eip) const
{
InterruptDisabler disabler;
auto& process = const_cast<Process&>(this->process());
ProcessPagingScope paging_scope(process);
Vector<FlatPtr, Profiling::max_stack_frame_count> backtrace;
backtrace.append(ebp);
backtrace.append(eip);
for (FlatPtr* stack_ptr = (FlatPtr*)ebp; process.validate_read_from_kernel(VirtualAddress(stack_ptr), sizeof(FlatPtr) * 2) && MM.can_read_without_faulting(process, VirtualAddress(stack_ptr), sizeof(FlatPtr) * 2); stack_ptr = (FlatPtr*)*stack_ptr) {
FlatPtr retaddr = stack_ptr[1];
backtrace.append(retaddr);

2
Kernel/Thread.h
View file

@ -97,7 +97,7 @@ public:
const Process& process() const { return m_process; }
String backtrace(ProcessInspectionHandle&) const;
Vector<FlatPtr> raw_backtrace(FlatPtr ebp) const;
Vector<FlatPtr> raw_backtrace(FlatPtr ebp, FlatPtr eip) const;
const String& name() const { return m_name; }
void set_name(const StringView& s) { m_name = s; }