[nsd-users] NSD TCP and UDP performance

Aaron Hopkins lists at die.net
Mon Nov 10 18:58:54 UTC 2008


On Fri, 16 Nov 2007, Wouter Wijngaards wrote:
> After the discussion on the mailing-list the other week the development
> team revisited the issues with respect to TCP-Nagle-algorithm and the
> the UDP performance increase by implementing multiple reads after a
> single select.
[...]
> You may expect these features to be available in 3.1.

>From my quick examination of NSD 3.2.0, these optimizations aren't yet
included.  Is there a revised timeline for implementing them?

I also just noticed that NSD select()s on the ability to write() for every
TCP reply.  In the common case, this is unnecessary and will lead to
slightly increased CPU utilization and reply latency versus optimistically
write()ing and falling back to select() if necessary.  Was this optimization
considered and deemed unnecessarily complex?

                                     -- Aaron



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