Problem with dummynet
Chuck Swiger
cswiger at mac.com
Thu Aug 11 16:59:13 GMT 2005
Volodya Pelekh wrote:
> Yes it set at default value
> sysctl kern.clockrate
> kern.clockrate: { hz = 100, tick = 10000, profhz = 1024, stathz = 128 }
>
> but in freebsd 4.5, 5.3 in my network this set in HZ 100 too, and i
> have not this problem on those computers
How much of a difference changing HZ makes may depend on a lot of things such
as whether you are using device polling, etc, but if you care about reducing
the latency observed by network stats to below 10 ms, adding:
kern.hz="1000"
...to /boot/loader.conf and rebooting is definitely worth the try. As the
manpage for dummynet itself says:
Generally, the following options are required:
options IPFIREWALL
options DUMMYNET
options HZ=1000 # strongly recommended
Additionally, one may want to increase the number of mbuf clusters (used
to store network packets) according to the sum of the bandwidth-delay
products and queue sizes of all configured pipes.
Also, you ought to upgrade that 4.5 system to 4.11 if you can, there are some
significant security issues which have been issued between the two, BTW.
--
-Chuck
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