On 16-09-12 06:26 PM, Eric Dumazet wrote:
On Mon, 2016-09-12 at 18:14 -0400, Jamal Hadi Salim wrote:
I noticed some very weird issues when I took that out.
Running sufficiently large amount of traffic (ping -f is sufficient)
I saw that when i did a dump it took anywhere between 6-15 seconds.
With the read_lock in place response was immediate.
I can go back and run things to verify - but it was very odd.
This was on uni processor ?
It was a VM.
Looks like typical starvation caused by aggressive softirq.
Well, then it is strange that in one case a tc dump of the rule
was immediate and in the other case it was consistent for 5-15
seconds.
Anyway, I suspect your kernel build has rcu_read_lock() and
rcu_read_unlock() as NOP ;)
Which doesnt give me a good feel if i tested this well ;->
I would like to try again with those two kernels just to
make sure i was not imagining this.
cheers,
jamal
