Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763167Ab3ECRRJ (ORCPT ); Fri, 3 May 2013 13:17:09 -0400 Received: from smtp30.i.mail.ru ([94.100.177.90]:46146 "EHLO smtp30.i.mail.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757735Ab3ECRRI (ORCPT ); Fri, 3 May 2013 13:17:08 -0400 X-Greylist: delayed 560 seconds by postgrey-1.27 at vger.kernel.org; Fri, 03 May 2013 13:17:07 EDT Message-ID: <5183FEB2.2090604@list.ru> Date: Fri, 03 May 2013 22:15:14 +0400 From: Stas Sergeev User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 MIME-Version: 1.0 To: Greg KH CC: Jarkko Huijts , Alan Cox , linux-usb@vger.kernel.org, linux-serial@vger.kernel.org, Linux kernel , Caylan Van Larson , "Rafael J. Wysocki" Subject: Re: Regression: ftdi_sio is slow (since Wed Oct 10 15:05:06 2012) References: <5183D196.2080305@list.ru> <20130503163008.GA30699@kroah.com> <5183F62A.1020801@list.ru> <20130503165231.GA1966@kroah.com> In-Reply-To: <20130503165231.GA1966@kroah.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam: Not detected X-Mras: Ok Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 575 Lines: 12 03.05.2013 20:52, Greg KH пишет: > What exactly is the "problem" being seen? OK, the problem is that while select() "stalls", the entire output queue is transmitted, and when the app writes more, there is already a big pause. In fact, the app calls select() before writing every char, so then the data transfer is very slow. -- 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/