From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34E8AC433F5 for ; Mon, 20 Dec 2021 10:45:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229612AbhLTKpZ (ORCPT ); Mon, 20 Dec 2021 05:45:25 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:58104 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229459AbhLTKpZ (ORCPT ); Mon, 20 Dec 2021 05:45:25 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id EE3C1B80E33 for ; Mon, 20 Dec 2021 10:45:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D431C36AE8; Mon, 20 Dec 2021 10:45:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1639997122; bh=2DzEFjxa8dcWu0VnnSctZJz/fpWAW00zYElRTGpHD+M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Uc/esLT2GMjuKtTOQOve2QW3VzzYnXNJzuhgwrWaiyP4/847uB2yjYKnXcbZuKVd/ Vj/kgcdQ3FF8e7mzCeaO2B5/NafGqokYYwI7xaBCuKuVqdOZZf2VXllwUOj5uqbDTD fJMG47P9uOKo5/AzqMbpKVRdRj1r2Rj53gTi1mdw= Date: Mon, 20 Dec 2021 11:45:20 +0100 From: Greg KH To: Filip =?utf-8?Q?=C5=BDaludek?= Cc: linux-usb@vger.kernel.org, Konrad Wilk Subject: Re: [External] : Re: data throttling under load when serial to usb adapter is used Message-ID: References: <738e20c6-c709-d149-fe48-ee89540fe38a@oracle.com> <67ff29fb-98cd-1835-ee6e-4eba67ff269c@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <67ff29fb-98cd-1835-ee6e-4eba67ff269c@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Mon, Dec 20, 2021 at 11:19:03AM +0100, Filip Žaludek wrote: > > > > > Using 'cat' is not a good way to ever use a serial port. Please use a > > tool that can properly detect and use the serial port flow control > > settings, which should prevent the issues you are seeing here. > > > > Is socat using flow control? If so, which settings, hardware or > > software flow control? > > > > Also please note that the usb-serial devices you are using here are > > _very_ cheap and not good for huge amounts of data like you seem to want > > to use here. I would recommend a much more robust usb-serial device if > > you need high data rates and good hardware flow control handling. Most > > of the time, the devices you have here do not even have any hardware > > flow control support as the manufacturers do not hook up those lines. > > So be careful. > > > > thanks, > > > > greg k-h > > > > > > Yes, you are right! Such gadget hardware is without hw flow control. I am using > serial line only to capture console logs. I've tested both commands also with > sw flow control ixon, ixoff with similar results. > > Hopefully somebody sitting on scarce big iron with both usb port and serial port > with proper hw flow control from this list gets attracted to kindly re-test. > > Interesting part for me is that only serial to usb direction is failing.. Makes sense, these devices are not designed for lots of high-speed data being sent to them. Please use a device that is designed for that if you wish to do this. thanks, greg k-h