title: Instruction to get the current time on x86
body: <p>Is there an x86 instruction to get the current time?</p>
  
  <p>Basically... something like a replacement for clock_get_time ... something with the minimum overhead... where I don't really care about getting the time in any specific format... as long as it's a format I can use.</p>
  
  <p>Basically I'm doing some work to "Detect how much PHYSICAL REAL LIFE TIME" has gone by... and I want to be able to measure time as frequently as possible!</p>
  
  <p>I guess you can imagine i'm doing something like a profiling app... :)</p>
  
  <p>I really need aggressively efficient access to the hardware time. So ideally... some ASM to get the time... store it somewhere... then massage it later into some format that I can actually process.</p>
  
  <p>I'm not interested in _rdtsc as that measures the number of cycles gone by. I need to know how much physical time has executed... not cycles which can vary due to thermal fluctations or so..</p>