Messages in this thread | | | Subject | Re: [PATCH net-next] tcp: minor optimization in tcp ack fast path processing | From | Eric Dumazet <> | Date | Wed, 7 Nov 2018 07:16:18 -0800 |
| |
On 11/07/2018 03:20 AM, Yafang Shao wrote: > Bitwise operation is a little faster.
> So I replace after() with (flag & FLAG_SND_UNA_ADVANCED) as this flag is > already set before. > > Cc: Joe Perches <joe@perches.com> > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > --- > net/ipv4/tcp_input.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c > index 2868ef2..0167015 100644 > --- a/net/ipv4/tcp_input.c > +++ b/net/ipv4/tcp_input.c > @@ -3610,7 +3610,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) > if (flag & FLAG_UPDATE_TS_RECENT) > tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq); > > - if (!(flag & FLAG_SLOWPATH) && after(ack, prior_snd_una)) { > + if (!(flag & FLAG_SLOWPATH) && (flag & FLAG_SND_UNA_ADVANCED)) { > /* Window is constant, pure forward advance. > * No more checks are required. > * Note, we use the fact that SND.UNA>=SND.WL2. >
What about reducing this to a single conditional jump ?
if ((flag & (FLAG_SLOWPATH | FLAG_SND_UNA_ADVANCED)) == FLAG_SND_UNA_ADVANCED) {
| |