On Mon May 19 12:26:00 EDT 2014, quans...@quanstro.net wrote: > On Mon May 19 10:04:28 EDT 2014, lu...@proxima.alt.za wrote: > > > i indirectly heard "go needs it", but that is not really a reason > > > i can understand technically. why must it be a system call? > > > > Actually, Go raised an important alert, quite indirectly: when using > > high resolution timers, the issue of opening a device, reading it and > > converting the input value to a binary value can and in this case is > > very expensive. > > > > Curiously, the actual symptom - I cannot remember how it came about - > > was that using the timer leaked file descriptors, or, more likely, > > gave the impression of leaking file descriptors. But the reality is > > that nanosecond accuracy cannot be achieved from reading a device by > > conventional means. > > i think my original question still stands. what is the purpose of timing, > what is the desired accuracy and precision, and is a relative or absolute > time wanted?
also, one cannot get close to 1ns precision with a system call. a system call takes a bare minimum of 400-500ns on 386/amd64. - erik
