Re: [chrony-users] How does chrony "speed up" the system clock

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Yes it would. If the clock were slowed by 500PPM (which is a large slew rate)
a 1 second sleep would take all of .5 milli seconds longer. Now chrony can
slow the clock more than that but only under severe circumstances and never by
more than 10%.

You can tell chrony to jump the clock if its error is too large. (that is an
infinite slew rate), but that will not happen. In normal operation the slew
rate may change by a few parts per million-- ie, it is not something to worry

William G. Unruh __| Canadian Institute for|____ Tel: +1(604)822-3273
Physics&Astronomy _|___ Advanced Research _|____ Fax: +1(604)822-5324
UBC, Vancouver,BC _|_ Program in Cosmology |____ unruh@xxxxxxxxxxxxxx
Canada V6T 1Z1 ____|____ and Gravity ______|_

On Sat, 2 Sep 2017, xxhdx1985126 wrote:

Hi, everyone

I'm a newbie to chrony. I saw these words in "chronyc manual page": "any error in the system clock
is corrected by slightly speeding up or slowing down the system clock until the error has been
removed, and then returning to the system clockʼs normal speed". I wonder what does the "speed up
the system clock" mean? Would it influence the execution of glibc APIs like "sleep"? I mean if
chrony decides to speed up the system clock, would sebsequent "sleep" function calls take less time
to return? And is there a max error bound in time for chrony?

Thanks very much:-)



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