will dynamic dhcpd.conf be supported in future releases

Ted Lemon Ted.Lemon at nominum.com
Fri Aug 11 00:06:38 UTC 2006

On Aug 10, 2006, at 4:02 PM, ashok singh wrote:
> stopping and starting takes more time than just handling the SIGHUP  
> for dynamic dhcpd.conf. The overall response time in both the cases  
> is my concern.

This is actually not true, unless you have a really slow dynamic  
linker.   Deallocating memory is not free - it costs CPU time, cache  
misses and page faults.   Furthermore, you still have to do all the  
work of re-parsing and re-allocating memory for the config file.    
You really are better off just starting from scratch, unless, as I  
say, you have a really slow dynamic linker.   Since dhcpd depends on  
very few shared libraries, I sincerely doubt that this is an issue.

I think you're imagining that the DHCP server could do some kind of  
incremental parse and thereby save time and prevent thrashing, but  
this isn't possible.   Or you may not realize that the server keeps  
the entire database and configuration in memory - it doesn't reread  
the configuration file every time a request comes in, as would, for  
example, a typical BOOTP server.

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