| Re: [chrony-users] Chrony 1.26 public server available - please try ... |
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On Fri, Aug 12, 2011 at 03:45:05PM +0100, Ed W wrote:
> I think I found a problem where my machine was lagging for some ms when
> load/iowait increased on that machine (it runs a number of virtual
> machines). I have increased the chrony priority with "-P 30" and the
> jitter is now tracking much lower
Interesting. With kernel timestamps it shouldn't matter if there is a
larger delay between capturing the packet and waking up the chrony
process or during processing of the packet unless it's after
the last timestamp is captured and before the response is sent.
> Any comments on the use of the priority level? (is it possible to cause
> a DOS by pinning the machine now that some task is running sched_fifo?).
> I could alternatively nice the process - I believe this still allows
> stuff to be rescheduled if the process goes out to lunch?
I think it should be safe unless an infinite loop is triggered.
When I was testing the maximum packet rate chrony can handle, its CPU
time was only few percent, the rest was kernel handling the network
traffic.
> Anyone using the server please comment on any change in latency since
> approx 15:00BST today?