Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753205AbbGVWxW (ORCPT ); Wed, 22 Jul 2015 18:53:22 -0400 Received: from svenbrauch.de ([46.38.239.95]:51928 "EHLO svenbrauch.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750779AbbGVWxV (ORCPT ); Wed, 22 Jul 2015 18:53:21 -0400 Subject: Re: [PATCH] Fix data loss in cdc-acm To: Peter Hurley References: <55AC1883.4050605@svenbrauch.de> <20150720172546.GF20628@localhost> <55AD38E5.1090807@svenbrauch.de> <1437486195.3823.13.camel@suse.com> <55AEBD06.6020402@svenbrauch.de> <55AED708.903@hurleysoftware.com> <55AEE805.9050204@svenbrauch.de> <55B01554.90201@hurleysoftware.com> Cc: Oliver Neukum , Johan Hovold , Linux Kernel Mailing List , One Thousand Gnomes , Toby Gray , linux-usb@vger.kernel.org, linux-serial@vger.kernel.org From: Sven Brauch X-Enigmail-Draft-Status: N1110 Message-ID: <55B01EDE.3050503@svenbrauch.de> Date: Thu, 23 Jul 2015 00:53:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <55B01554.90201@hurleysoftware.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="aHBa0c65wG0RCea0gbdNJ5cbXqNdpLoxA" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2527 Lines: 64 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --aHBa0c65wG0RCea0gbdNJ5cbXqNdpLoxA Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi, On 23/07/15 00:12, Peter Hurley wrote: > The premature unthrottle actually leads to the data loss but the thrott= ling > with a mere 2K left is _way too late_. Ok, yes, I think so too. > 10ms is a _really_ long time for a cpu not to attend to a kworker. > Which raises 2 questions: > 1. What are the termios settings of the tty receiving input? Is it 'raw= ' > mode or typical terminal mode (icanon, echo, etc.) or something else= ? In my test code, I open the tty like fd =3D open("/dev/ttyACM0", O_RDWR | O_NOCTTY | O_NONBLOCK); I don't make any other changes to the default settings. To be honest, I'm not sure in which mode it is operating then (I was assuming raw, but I might be wrong?). > 2. Are there RT threads that are hogging cpu time? I can't see any, I think the only thing which occasionally goes to RT is pulseaudio (but during at least some of the tests I wasn't even playing audio, so that sounds very unplausible to me). I also cannot see a correlation between failure rate and CPU load. Best regards, Sven --aHBa0c65wG0RCea0gbdNJ5cbXqNdpLoxA Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJVsB7eAAoJEGjKjjjEuz9LRzAP/AgfCXWXfF5glUGvlfyIYT6v gzIOJYXqPqLh/rIJlxmEbtj6YXyxS6WdfXXSxHl2KNbR5QFTNsdrqCpfwmkU8jf0 ClZ8pn+jKLV1YFrJHgqNkaSHNtQ7uK/O2rDgsqOwuMZvrZdFsmaufRYGy+dYRApE 3CO0xb028suvlmipUkLQGysRyeDsXPr8vSa4xmOcMxIKj9UWGSXGuXvXpxGdHYHl xNLTUO7UW5IKQhnBMMr7sMfPL9hEyEiK97ELLaUd/ilQS6V4OPrZJHB64Lr4QP7M 8IORX8avyYlxcG/yrXen7npMsmSOz6F28+Mh6SBrDU1UWGUQUI7dvsb3puKWtjUX UibYA3uu6sixTJKHj+iSRIfnuNab7azrwU28wLYNVDPZHFYxx9ofayaOnVVvQ66E oEY405YvSR2DiNs5VXVuWi1k3wRJC+AhSVRdHOpmgnqjCiriRQPmZXtofYJ0Vhq5 P5/aHYZ1ZEq4k2lBe80sR4GJR0aDjGEGIy3iSTDQbMayDOy/AMoMUOZqn544aMMd 3ql4ADuffEJRrb1JPNhyp1xPoGHvouAkFwdYPV+SuldTwc/9j2aMsvoatjcPnnGQ fdY7g49myxROquNWptllrdppnvms44Kml2rniRCf9ydjcbOtJJ/JhQQpNt2vlhjK GrkThbdcLCK3984QizCI =q8Yh -----END PGP SIGNATURE----- --aHBa0c65wG0RCea0gbdNJ5cbXqNdpLoxA-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/