Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030213AbcK3K3H (ORCPT ); Wed, 30 Nov 2016 05:29:07 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:41281 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964851AbcK3K3C (ORCPT ); Wed, 30 Nov 2016 05:29:02 -0500 Date: Wed, 30 Nov 2016 11:28:57 +0100 From: Pavel Machek To: Eric Dumazet Cc: David Miller , lsanfil@marvell.com, peppe.cavallaro@st.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: stmmac ethernet in kernel 4.4: coalescing related pauses? Message-ID: <20161130102857.GA14296@amd> References: <20161123105125.GA26394@amd> <20161128.095431.856183735501262965.davem@davemloft.net> <1480347103.18162.58.camel@edumazet-glaptop3.roam.corp.google.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="HlL+5n6rz5pIUxbD" Content-Disposition: inline In-Reply-To: <1480347103.18162.58.camel@edumazet-glaptop3.roam.corp.google.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1538 Lines: 50 --HlL+5n6rz5pIUxbD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon 2016-11-28 07:31:43, Eric Dumazet wrote: > On Mon, 2016-11-28 at 09:54 -0500, David Miller wrote: > > From: Lino Sanfilippo > > Date: Mon, 28 Nov 2016 14:07:51 +0100 > >=20 > > > Calling skb_orphan() in the xmit handler made this issue disappear. > >=20 > > This is not the way to handle this problem. > >=20 > > The solution is to free the SKBs in a timely manner after the > > chip has transmitted the frame. >=20 > Note that the 'pauses' described by Pavel are also caused by a too small > SO_SNDBUF value on the UDP socket. >=20 > An immediate fix, with no kernel change is to increase it. >=20 > echo 1000000 >/proc/sys/net/core/wmem_default Thanks a lot. For the record, that works around the problem, too. (Or at least helps a lot; it may be possible that problem still remains if continuous stream of packets is going to trigger this, if I read the sources correctly.) Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --HlL+5n6rz5pIUxbD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlg+qekACgkQMOfwapXb+vKB8gCcDZGH6W4A5WADPi/NDNgf9RfF RWcAn0gyWtVoGTpGzrtbo23spNXbheYp =NrBz -----END PGP SIGNATURE----- --HlL+5n6rz5pIUxbD--