Messages in this thread | | | Subject | Re: [ANNOUNCE] ktimers subsystem | From | Thomas Gleixner <> | Date | Tue, 20 Sep 2005 00:44:09 +0200 |
| |
On Mon, 2005-09-19 at 15:24 -0700, Christoph Lameter 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. > > You can ask lots of application vendors the same question because its all > over lots of user space code. The fact is that gettimeofday() / > clock_gettime() efficiency is very critical to the performance of many > applications on Linux. That is why the addtion of one add instruction may > better be carefully considered.
Hmm. I don't understand the argument line completely.
1. The kernel has to provide ugly mechanisms because a lot of applications implementations are doing the Wrong Thing ?
2. All gettimeofday implementations I have looked at do a lot of math anyway, so its definitely more interesting to look at those oddities rather than discussing a single add. John Stulz timeofday rework have a clean solution for this - please do not argue about the div64 in his original patches which he is reworking at the moment.
> Many platforms can execute gettimeofday > without having to enter the kernel.
Which ones ? How is this achieved with respect to all the time adjust, correction... code ?
tglx
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |