Messages in this thread | | | Date | Thu, 24 Jun 2004 12:29:55 +0530 | From | abhijit <> | Subject | Re: do_gettimeofday( ) precision? |
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On Thu, 24 Jun 2004 12:13:11 +0530, abhijit <slashdev@gmail.com> wrote: > > basically i want some counter w/ microsend resolution that fits into 32 bits. > couple of possible solutions come to my mind: > > [1] use TSC and convert it to microsec > [2] use get_timeofday( ) and convert to microsec > [3] use xtime variable directly and convert to microsec > (any other ways?) > > conversion in [1] will be costly (a div involved). > conversion in [2]/[3] can be done using bit operators. (usec|sec << 20) > but [2] will incur function call overhead which i'd like to avoid. > > so is using xtime directly ok and reliable?
ok. after reading up the source, i think xtime isn;t updated frequently and will not have the required resolution :( so calling do_gettimeofday() seems the only way out (unless somebody has any other idea).
btw why isn't do_gettimeofday( ) declared as "inline". so its bit cheaper to call especially where you are timestamping (say packets) often.
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