| RE: [chrony-users] High-performance NTP servers |
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Miroslav,
More performance is always nice.
But never at the cost of accuracy.
I think for an NTP server, achieving the best accuracy should be the primary goal.
Adri.
> -----Original Message-----
> From: Miroslav Lichvar [mailto:mlichvar@xxxxxxxxxx]
> Sent: woensdag 27 juli 2016 09:10
> To: chrony-users@xxxxxxxxxxxxxxxxxxxx
> Subject: [chrony-users] High-performance NTP servers
>
> I was wondering if anyone here has NTP servers that are handling so much
> NTP traffic that the CPU is the limiting factor and if there is any interest in
> optimizing chrony for better performance.
>
> The Linux kernel has special system calls that can receive or send multiple
> packets at once. This reduces the amount of time spent in switching
> between the kernel and user-space. I ran some experiments and it seems
> they do improve the maximum packet rate nicely. On a PC-based server the
> rate improved from about 210000/sec to 260000/sec when the receiving code
> was modified, and to about 350000/sec when also the sending code was
> modified. On a low-end router running OpenWrt the rate went from about
> 2200/sec to 2800/sec when the receiving was modified.
>
> This was just a quick hack to see how it works. If it should be implemented
> properly, improving the receiving code would be easy, but the sending would
> be much more difficult and it may also have a negative effect on the
> accuracy. Would there be any interest in improvements like that? I'm
> considering to do the former, but not the latter.
>
> --
> Miroslav Lichvar
>
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