Commit 3046e2f5 authored by Eliezer Tamir's avatar Eliezer Tamir Committed by David S. Miller

net: add cpu_relax to busy poll loop

Add a cpu_relaxt to sk_busy_loop.

Julie Cummings reported performance issues when hyperthreading is on.
Arjan van de Ven observed that we should have a cpu_relax() in the
busy poll loop.
Reported-by: default avatarJulie Cummings <julie.a.cummings@intel.com>
Signed-off-by: default avatarEliezer Tamir <eliezer.tamir@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 64c3b252
...@@ -123,6 +123,7 @@ static inline bool sk_busy_loop(struct sock *sk, int nonblock) ...@@ -123,6 +123,7 @@ static inline bool sk_busy_loop(struct sock *sk, int nonblock)
/* local bh are disabled so it is ok to use _BH */ /* local bh are disabled so it is ok to use _BH */
NET_ADD_STATS_BH(sock_net(sk), NET_ADD_STATS_BH(sock_net(sk),
LINUX_MIB_BUSYPOLLRXPACKETS, rc); LINUX_MIB_BUSYPOLLRXPACKETS, rc);
cpu_relax();
} while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) && } while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) &&
!need_resched() && !busy_loop_timeout(end_time)); !need_resched() && !busy_loop_timeout(end_time));
......
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