From mboxrd@z Thu Jan 1 00:00:00 1970
Return-Path: <stephen@networkplumber.org>
Received: from mail-pl0-f49.google.com (mail-pl0-f49.google.com
[209.85.160.49]) by dpdk.org (Postfix) with ESMTP id B4DBF235
for <dev@dpdk.org>; Mon, 23 Jul 2018 19:38:00 +0200 (CEST)
Received: by mail-pl0-f49.google.com with SMTP id j8-v6so457844pll.12
for <dev@dpdk.org>; Mon, 23 Jul 2018 10:38:00 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=networkplumber-org.20150623.gappssmtp.com; s=20150623;
h=date:from:to:cc:subject:message-id:in-reply-to:references
:mime-version:content-transfer-encoding;
bh=vm99mG80eSZGod6m8SZDxid2I7d18AN4xjR0vWlPLHM=;
b=ROuum/GKXJUnwIVOXwDMhlS7HBJ9r8iEjJW6fG2iUs33n/j7gYQ0mX4FrdKACFLBJb
eX/DnGlXfkOzhWLkJpKTxjwzu8LEzcmMESmSSYqYySW4exSpQRQaDqUvICS2E5Wz8O3F
+Pnt/+MEkN5iY3YnAfjHTFwTgSxCdTSjRrwQBS254ihTFT2nWvCpsoP05kdxZa0dcDwB
qvXJTGJJnDm/hC/bFElgFx5ql5Ls4zqkfBHX0nJ60OCNWfIwnMxkUNicK7B2K3XUaNap
TVh//HNpQ0B8unuod4JPXhY/u2HtLN+UiamwHRceUZYp35GkWyicwAXnskasVCwFWM20
MLsg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=1e100.net; s=20161025;
h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to
:references:mime-version:content-transfer-encoding;
bh=vm99mG80eSZGod6m8SZDxid2I7d18AN4xjR0vWlPLHM=;
b=QMWoOHX5vXvUfpGssEvuaWFpFTTLmQb2byoREkLVNgSIsJRknvC71oFvj9B8Fml/Ri
ZGYkOaYd8dqGUcIR2NmJR+AIKFzJ4xezxhUgMCkGCG4N1tSfvJ2+zJMlDM4cjvMCGddJ
SZnxPMXnb3lv0gw9KXCIBIWajmWBJlL3+yY5VrRvp43U+5rPO0ifY9t76f/vulat++eH
xWjsgNCZyrhu0/8Lt8hwG5QTjx9OD49PP4PTYWYAH22gkuVGepTw5mNcgLw8qkmZHwhl
iabeODuzi3pWdF0ao3DCUHeOVurjx+4ETPRIUa14VAZnvrVGFXyW9qPkNJAn4Aj/Tszt
nJmQ==
X-Gm-Message-State: AOUpUlFlN4ThVvfPa8Xpaf2wPKaAz2QWIeE9L4VvrgoRJVhkzZvEQ+P9
T4H/6Bk8XMVV/bT4mYc2PRbVL/i8OaY=
X-Google-Smtp-Source: AAOMgpfN1GKctoBonfhFcly2Ru1j5eWKUQAa7P9Q86yabdND+8YvUT7dM9IR0oQn0mQVqhsDA0BspQ==
X-Received: by 2002:a17:902:2927:: with SMTP id
g36-v6mr13503212plb.303.1532367479936;
Mon, 23 Jul 2018 10:37:59 -0700 (PDT)
Received: from xeon-e3 (204-195-22-127.wavecable.com. [204.195.22.127])
by smtp.gmail.com with ESMTPSA id 16-v6sm20511087pfo.164.2018.07.23.10.37.59
(version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256);
Mon, 23 Jul 2018 10:37:59 -0700 (PDT)
Date: Mon, 23 Jul 2018 10:37:57 -0700
From: Stephen Hemminger <stephen@networkplumber.org>
To: Morten =?UTF-8?B?QnLDuHJ1cA==?= <mb@smartsharesystems.com>
Cc: "Olivier Matz" <olivier.matz@6wind.com>, <dev@dpdk.org>
Message-ID: <20180723103757.47e4c26b@xeon-e3>
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35B421EE@smartserver.smartshare.dk>
References: <98CBD80474FA8B44BF855DF32C47DC35B421EE@smartserver.smartshare.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [dpdk-dev] rte_mbuf library likely()/unlikely()
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
<mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
<mailto:dev-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Mon, 23 Jul 2018 17:38:01 -0000
On Mon, 23 Jul 2018 15:53:42 +0200
Morten Br=C3=B8rup <mb@smartsharesystems.com> wrote:
> Hi Olivier,
>=20
> =20
>=20
> I noticed that __rte_pktmbuf_read() could do with an unlikely(), so I wen=
t through the entire library. Here are my suggested modifications.
>=20
> =20
>=20
> =20
>=20
> diff -bu rte_mbuf.c.orig rte_mbuf.c
>=20
> --- rte_mbuf.c.orig 2018-07-23 15:13:22.000000000 +0200
>=20
> +++ rte_mbuf.c 2018-07-23 15:32:53.000000000 +0200
>=20
> @@ -173,19 +173,19 @@
>=20
> {
>=20
> unsigned int nb_segs, pkt_len;
>=20
> =20
>=20
> - if (m =3D=3D NULL)
>=20
> + if (unlikely(m =3D=3D NULL))
>=20
> rte_panic("mbuf is NULL\n");
>=20
> =20
Adding is unlikely is not necessary since rte_panic is marked with cold att=
ribute
which has the same effect.