From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hua Zhong Subject: [PATCH]: suspicious unlikely usage in tcp_transmit_skb() Date: Mon, 24 Apr 2006 16:25:39 -0700 Message-ID: <444D5E73.7020803@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from nz-out-0102.google.com ([64.233.162.194]:33708 "EHLO nz-out-0102.google.com") by vger.kernel.org with ESMTP id S1751480AbWDXXZm (ORCPT ); Mon, 24 Apr 2006 19:25:42 -0400 Received: by nz-out-0102.google.com with SMTP id r28so1005366nza for ; Mon, 24 Apr 2006 16:25:41 -0700 (PDT) To: davem@davemloft.net, netdev@vger.kernel.org Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hi, I am developing a profiling tool to check if likely/unlikely usages are wise. I find that the following one is always a miss: # Hit # miss Function:Filename@Line ! 0 50505 tcp_transmit_skb():net/ipv4/tcp_output.c@468 There is a chance that my tool is buggy, but I just want to confirm with you whether this does look suspicious and what your opinion is. Signed-off-by: Hua Zhong diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index a28ae59..743016b 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -465,7 +465,7 @@ #define SYSCTL_FLAG_SACK 0x4 TCP_INC_STATS(TCP_MIB_OUTSEGS); err = icsk->icsk_af_ops->queue_xmit(skb, 0); - if (unlikely(err <= 0)) + if (likely(err <= 0)) return err; tcp_enter_cwr(sk);