On 12/12/05, George Anzinger <[email protected]> wrote: > john stultz wrote: > > On Mon, 2005-12-12 at 20:00 +0000, Shailabh Nagar wrote: > > > >>john stultz wrote: > >> > >>>On Mon, 2005-12-12 at 19:31 +0000, Shailabh Nagar wrote: > >>> > >>> > >>>>Christoph Lameter wrote: > >>>> > >>>> > >>>>>On Wed, 7 Dec 2005, Shailabh Nagar wrote: > >>>>> > >>>>>>+void getnstimestamp(struct timespec *ts) > >>>>> > >>>>>There is already getnstimeofday in the kernel. > >>>> > >>>>Yes, and that function is being used within the getnstimestamp() being > >>>>proposed. > >>>>However, John Stultz had advised that getnstimeofday could get affected > >>>>by calls to > >>>>settimeofday and had recommended adjusting the getnstimeofday value with > >>>>wall_to_monotonic. > >>>> > >>>>John, could you elaborate ? > >>> > >>>I think you pretty well have it covered. > >>> > >>>getnstimeofday + wall_to_monotonic should be higher-res and more > >>>reliable (then TSC based sched_clock(), for example) for getting a > >>>timestamp. > >>> > >>>There may be performance concerns as you have to access the clock > >>>hardware in getnstimeofday(), but there really is no other way for > >>>reliable finely grained monotonically increasing timestamps. > >>> > > > > > >>Thanks, that clarifies. I guess the other underlying concern here would be > >>whether these > >>improvements (in resolution and reliability) should be going into > >>getnstimeofday() > >>itself (rather than creating a new func for the same) ? Or is it better to > >>leave > >>getnstimeofday as it is ? > > > > > > No, getnstimeofday() is very much needed to get a nanosecond grained > > wall-time clock, so a new function is needed for the monotonic clock. > > > > In my timeofday re-work I have used the name "get_monotonic_clock()" and > > "get_monotonic_clock_ts()" for basically the same functionality > > (providing a ktime and a timespec respectively). You might consider > > naming it as such, but resolving these naming collisions shouldn't be > > too difficult either way. > > Indeed. Lets use a name with "monotonic" in it, please. And, > possibly not "clock". How about get_nsmonotonic_time() or some such?
I agree -- personal preference, though, I prefer units at the end, i.e. get_monotonic_time_ns() or get_monotonic_time_nsecs(). Thanks, Nish ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_idv37&alloc_id865&op=click _______________________________________________ ckrm-tech mailing list https://lists.sourceforge.net/lists/listinfo/ckrm-tech
