# Is 12.0-CURRENT "slower" compaired to say 11.0-CURRENT?



## JamesElstone (Dec 10, 2016)

Hi All,

Have a number of nodes using a mix of run(4) in a bridge with an em0(4) interfaces. All is functionally well.

However, I have found that releng/11.0 has a higher throughput than a snapshot of head (12-CURRENT) on an arm processor, in a controlled RF environment.

The difference is about 23% less throughput when using a snapshot of head (r308737) compared to releng/11.0 (r306211).

The only optimisation I have made is `debug.witness.watch=0` set in /boot/loader.conf to twiddle WITNESS off.  

Is this to be expected for a snapshot of head, or is something up?  As a punt I am guessing that head has a load of additional debug overhead that could account for this?

The wisdom of the forum would be greatly received!

James


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## pkubaj (Dec 10, 2016)

https://svnweb.freebsd.org/base/head/UPDATING?view=co


> NOTE TO PEOPLE WHO THINK THAT FreeBSD 12.x IS SLOW:
> FreeBSD 12.x has many debugging features turned on, in both the kernel
> and userland.  These features attempt to detect incorrect use of
> system primitives, and encourage loud failure through extra sanity
> ...


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## scottro (Dec 11, 2016)

Just to point out that there is a GENERIC-NODEBUG kernel that makes it pretty easy. If you run `make kernel KERNCONF=GENERIC-NODEBUG` and reboot, things will be faster. 
Short answer, yes, HEAD, by default, has debugging code, the easy way to get rid of it is to use the nodebug kernel.


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## SirDice (Dec 12, 2016)

Topics about unsupported FreeBSD versions


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