mirror of
https://github.com/RGBCube/serenity
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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
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#include <stdio.h>
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#include <unistd.h>
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#ifdef __cplusplus
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struct Stopwatch {
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union SplitQword {
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struct {
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uint32_t lsw;
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uint32_t msw;
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};
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uint64_t qw { 0 };
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};
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public:
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Stopwatch(const char* name)
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: m_name(name)
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{
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read_tsc(&m_start.lsw, &m_start.msw);
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}
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~Stopwatch()
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{
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SplitQword end;
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read_tsc(&end.lsw, &end.msw);
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uint64_t diff = end.qw - m_start.qw;
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dbgprintf("Stopwatch(%s): %Q ticks\n", m_name, diff);
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}
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private:
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const char* m_name { nullptr };
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SplitQword m_start;
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};
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#endif // __cplusplus
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__BEGIN_DECLS
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int module_load(const char* path, size_t path_length);
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int module_unload(const char* name, size_t name_length);
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int profiling_enable(pid_t);
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int profiling_disable(pid_t);
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__END_DECLS
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