[LinuxPPS] cross posting [time-nuts] NTP API on Linux 2.6.26
Udo van den Heuvel
udovdh at xs4all.nl
Sun Jan 11 10:54:04 CET 2009
Hal V. Engel wrote:
> On Sunday 11 January 2009 00:45:40 Udo van den Heuvel wrote:
>> Hal V. Engel wrote:
>>> checking for clock_gettime... yes
>>> checking for clock_settime... yes
>> I see it with teh more or less stock fedora rpm.
>>
>> Still the precision is in 1.x us. Not 0.00x us....
>>
>> I use:
>> Name : glibc Relocations: (not relocatable)
>> Version : 2.9 Vendor: Fedora Project
>>
>> So what could be lacking?
>> How can I check why it doesn't give me the extra precision?
>
> Have you patched glibc with the nanosecond patch set located here
Stock Fedora glibc here.
> time constant 4, precision 0.001 us, tolerance 500 ppm,
>
> The precision listed here is different from the precision you see in your sys
> log. In this case it will be 1.000 us if ntp is running in microsecond mode
> and 0.001 us if ntp is in nanosecond mode. And to change this you need to
> use one of the patches listed above. I was seeing this even before I linked
> in librt and linking in librt will not change this.
Ah, so that is the extra ingredient.
Probably we need to ask redhat to include this patch into the glibc?
Or is there alread a bu for this?
Udo
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