Re: Scalability of interface creation and deletion

Alex Bligh
2011-05-08T08:06:14Z

Eric,

> By the way, if I change HZ from 1000 to 100 I now have ten times slower
> result :
>
># ip link add link eth0 eth0.103 type vlan id 103
># time ip link del eth0.103
>
> real 0m0.430s
> user 0m0.000s
> sys 0m0.000s
>
> So all this is related to your HZ value, even in a CONFIG_NO_HZ=y
> kernel.

That's very mysterious.

> Alex, I guess you have HZ=250 ?

I have HZ=100. I am basically using the Ubuntu default with
localmodconfig to make compile times sensible.

amb@nattytest:~$ cd kernel/linux-2.6/
amb@nattytest:~/kernel/linux-2.6$ fgrep HZ .config
CONFIG_RCU_FAST_NO_HZ=y
CONFIG_NO_HZ=y
CONFIG_HZ_100=y
# CONFIG_HZ_250 is not set
# CONFIG_HZ_300 is not set
# CONFIG_HZ_1000 is not set
CONFIG_HZ=100
# CONFIG_MACHZ_WDT is not set

--
Alex Bligh