From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Guinot Subject: Re: [PATCH] net: mvneta: fix handling of the Tx descriptor counter Date: Mon, 13 Nov 2017 16:36:14 +0100 Message-ID: <20171113153614.GN18407@kw.sim.vm.gnt> References: <20171108165835.13453-1-simon.guinot@sequanux.org> <20171111.184504.2151388779461931723.davem@davemloft.net> <20171113145115.GM18407@kw.sim.vm.gnt> <20171113.235414.987480304119622711.davem@davemloft.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="68uOmRXIw+u8y5pO" Cc: thomas.petazzoni@free-electrons.com, netdev@vger.kernel.org, musv@gmx.de, andreas.tobler@cloudguard.ch, gregory.clement@free-electrons.com, antoine.tenart@free-electrons.com, mw@semihalf.com, stable@vger.kernel.org To: David Miller Return-path: Received: from vm1.sequanux.org ([188.165.36.56]:51825 "EHLO vm1.sequanux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753102AbdKMPgU (ORCPT ); Mon, 13 Nov 2017 10:36:20 -0500 Content-Disposition: inline In-Reply-To: <20171113.235414.987480304119622711.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: --68uOmRXIw+u8y5pO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Nov 13, 2017 at 11:54:14PM +0900, David Miller wrote: > From: Simon Guinot > Date: Mon, 13 Nov 2017 15:51:15 +0100 >=20 > > IIUC the driver stops the queue if a threshold of 316 Tx descriptors is > > reached (default and worst value). >=20 > That's a lot of latency. OK, then I'll keep the "tx_pending > 255" flushing condition. But note there is no other software mechanism to limit the Tx latency inside the mvneta driver. Should we add something ? And is that not rather the job of the network stack to keep track of the latency and to limit the txq size ? --68uOmRXIw+u8y5pO Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAloJu+4ACgkQgtp0PDeOcDr7vwCfYSDwWnHyYsH7BWlWlVY66wS7 IwgAoJKwJ/6jP6LN+6hXW+e5nlepHITh =jMkR -----END PGP SIGNATURE----- --68uOmRXIw+u8y5pO--