On Wed, 2013-05-22 at 12:26 -0700, Eric Dumazet wrote:
> On Wed, 2013-05-22 at 11:20 -0700, Joe Perches wrote:
> > On Wed, 2013-05-22 at 10:47 -0700, Eric Dumazet wrote:
> > > nf_conntrack_lock is a monolithic lock and suffers from huge contention
> > > on current generation servers (8 or more core/threads).
> > []
> > > diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
> > []
> > > @@ -76,7 +76,8 @@ struct nf_conn {
> > > plus 1 for any connection(s) we are `master' for */
> > > struct nf_conntrack ct_general;
> > >
> > > - spinlock_t lock;
> > > + spinlock_t lock;
> > > + u16 cpu;
> > trivia:
> > What's the real value in not using int here?
> On some machines, sizeof(spinlock_t) is 2
> So this addition doesn't increase size of the structure, as I fill a
> hole.
> Thats the case on x86 when NR_CPUS < 256
Ahh, nice.
It might also be nice to mark it if ever more than a u16
brace/flock/coven/cluster worth of cpus become feasible
as it seems int is used almost everywhere else.
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