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    performance counters: core code · 0793a61d
    Thomas Gleixner 提交于
    Implement the core kernel bits of Performance Counters subsystem.
    
    The Linux Performance Counter subsystem provides an abstraction of
    performance counter hardware capabilities. It provides per task and per
    CPU counters, and it provides event capabilities on top of those.
    
    Performance counters are accessed via special file descriptors.
    There's one file descriptor per virtual counter used.
    
    The special file descriptor is opened via the perf_counter_open()
    system call:
    
     int
     perf_counter_open(u32 hw_event_type,
                       u32 hw_event_period,
                       u32 record_type,
                       pid_t pid,
                       int cpu);
    
    The syscall returns the new fd. The fd can be used via the normal
    VFS system calls: read() can be used to read the counter, fcntl()
    can be used to set the blocking mode, etc.
    
    Multiple counters can be kept open at a time, and the counters
    can be poll()ed.
    
    See more details in Documentation/perf-counters.txt.
    Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
    Signed-off-by: NIngo Molnar <mingo@elte.hu>
    0793a61d
syscalls.h 27.8 KB