Re: Scalability of interface creation and deletion

Octavian Purdila
2011-05-09T21:46:06Z

On Sat, May 7, 2011 at 6:54 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:

>
> synchronize_rcu() calls are not consuming cpu, they just _wait_
> rcu grace period.
>
> I suggest you read Documentation/RCU files if you really want to :)
>
> If you want to check how expensive it is, its quite easy:
> add a trace in synchronize_net()
>
<snip>

I proposed adding a "wait" software counter to perf [1] a while ago,
which would allow people identify sync_rcu hotspots:

http://marc.info/?l=linux-kernel&m=129188584110162

I don't know how much visibility it got, so given this context, I
thought of bringing it up again :)