mirror of
https://github.com/RGBCube/serenity
synced 2025-07-23 17:17:42 +00:00
4a8683ea68
This patch implements a simple version of the futex (fast userspace mutex) API in the kernel and uses it to make the pthread_cond_t API's block instead of busily sched_yield(). An arbitrary userspace address is passed to the kernel as a "token" that identifies the futex and you can then FUTEX_WAIT and FUTEX_WAKE that specific userspace address. FUTEX_WAIT corresponds to pthread_cond_wait() and FUTEX_WAKE is used for pthread_cond_signal() and pthread_cond_broadcast(). I'm pretty sure I'm missing something in this implementation, but it's hopefully okay for a start. :^)
52 lines
992 B
C++
52 lines
992 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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#define FUTEX_WAIT 1
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#define FUTEX_WAKE 2
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int futex(int32_t* userspace_address, int futex_op, int32_t value, const struct timespec* timeout);
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__END_DECLS
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