Messages in this thread | | | Date | Mon, 19 Sep 2005 22:57:37 -0600 | From | "Christopher Friesen" <> | Subject | Re: [ANNOUNCE] ktimers subsystem |
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Thomas Gleixner wrote: > On Mon, 2005-09-19 at 16:39 -0600, Christopher Friesen wrote: > >>Thomas Gleixner wrote:
>>>We should rather ask glibc people why gettimeofday() / clock_getttime() >>>is called inside the library code all over the place for non obvious >>>reasons.
>>--flight-recorder style logs
> If you want to implement such stuff efficiently you rely on rdtscll() on > x86 or other monotonic easy accessible time souces and not on a > permanent call to gettimeofday.
Not portable across architectures, and doesn't work across all smp/numa environments. Also not easy to compare with other nodes on the network, whereas with ntp-synch'd nodes you can use gettimeofday() for quite accurate correlations.
> Please beware me of red herrings. If application developers code with > respect to random OS worst case behaviour then they should not complain > that OS N is having an additional add instruction in one of the pathes.
Actually I'm not complaining about additional add instructions. I was just suggesting some reasons why apps might reasonably want to know the time frequently.
Chris
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