[dns-operations] DNS server benchmarking sanity check

Paul Vixie paul at redbarn.org
Tue Aug 16 02:48:57 UTC 2016

bert hubert wrote:
> On Mon, Aug 15, 2016 at 03:38:52PM -0400, Jared Mauch wrote:
>> Moving from using send() to sendmsg() can help performance as well as
>> other tuning, but these tend to be less portable and avoided by developers
>> in my experience.  Simply put, this is the one case where I would still use
> So here is something someone might want to try if we don't find time for it
> first.
> I experimented a bit with using the interface for retrieving errors for UDP
> sockets.  Normally we connect() outgoing datagram sockets so we get errors
> via recv().  This allows us to more quickly discover a UDP port 53 that is
> closed.  But I wanted to see if we could make this work without connect().

you can get this done by reading and parsing the icmp socket, too. this 
requires no modernity in the kernel or system call interface, and 
drastically speeds up dead server detection.

P Vixie

More information about the dns-operations mailing list