b32e961a84
The kernel now supports basic profiling of all the threads in a process
by calling profiling_enable(pid_t). You finish the profiling by calling
profiling_disable(pid_t).
This all works by recording thread stacks when the timer interrupt
fires and the current thread is in a process being profiled.
Note that symbolication is deferred until profiling_disable() to avoid
adding more noise than necessary to the profile.
A simple "/bin/profile" command is included here that can be used to
start/stop profiling like so:
$ profile 10 on
... wait ...
$ profile 10 off
After a profile has been recorded, it can be fetched in /proc/profile
There are various limits (or "bugs") on this mechanism at the moment:
- Only one process can be profiled at a time.
- We allocate 8MB for the samples, if you use more space, things will
not work, and probably break a bit.
- Things will probably fall apart if the profiled process dies during
profiling, or while extracing /proc/profile
47 lines
848 B
C++
47 lines
848 B
C++
#pragma once
|
|
|
|
#include <stdio.h>
|
|
#include <unistd.h>
|
|
|
|
#ifdef __cplusplus
|
|
|
|
struct Stopwatch {
|
|
union SplitQword {
|
|
struct {
|
|
uint32_t lsw;
|
|
uint32_t msw;
|
|
};
|
|
uint64_t qw { 0 };
|
|
};
|
|
|
|
public:
|
|
Stopwatch(const char* name)
|
|
: m_name(name)
|
|
{
|
|
read_tsc(&m_start.lsw, &m_start.msw);
|
|
}
|
|
|
|
~Stopwatch()
|
|
{
|
|
SplitQword end;
|
|
read_tsc(&end.lsw, &end.msw);
|
|
uint64_t diff = end.qw - m_start.qw;
|
|
dbgprintf("Stopwatch(%s): %Q ticks\n", m_name, diff);
|
|
}
|
|
|
|
private:
|
|
const char* m_name { nullptr };
|
|
SplitQword m_start;
|
|
};
|
|
|
|
#endif // __cplusplus
|
|
|
|
__BEGIN_DECLS
|
|
|
|
int module_load(const char* path, size_t path_length);
|
|
int module_unload(const char* name, size_t name_length);
|
|
|
|
int profiling_enable(pid_t);
|
|
int profiling_disable(pid_t);
|
|
|
|
__END_DECLS
|