From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26252 invoked by alias); 9 Jul 2014 17:19:33 -0000 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Received: (qmail 25969 invoked by uid 89); 9 Jul 2014 17:19:29 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=0.3 required=5.0 tests=AWL,BAYES_20,RCVD_IN_DNSWL_NONE,SPF_SOFTFAIL autolearn=no version=3.3.2 X-HELO: qmta09.emeryville.ca.mail.comcast.net Received: from qmta09.emeryville.ca.mail.comcast.net (HELO qmta09.emeryville.ca.mail.comcast.net) (76.96.30.96) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 09 Jul 2014 17:19:28 +0000 Received: from omta04.emeryville.ca.mail.comcast.net ([76.96.30.35]) by qmta09.emeryville.ca.mail.comcast.net with comcast id QGnL1o0060lTkoCA9HKToo; Wed, 09 Jul 2014 17:19:27 +0000 Received: from [10.1.5.114] ([216.34.91.132]) by omta04.emeryville.ca.mail.comcast.net with comcast id QHHK1o00G2rLPg88QHHMXZ; Wed, 09 Jul 2014 17:17:25 +0000 Message-ID: <53BD791F.6040807@acm.org> Date: Wed, 09 Jul 2014 17:19:00 -0000 From: David Rothenberger User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: cygwin@cygwin.com Subject: Re: Severe performance degradation of writev References: <20140707101049.GI1803@calimero.vinschen.de> <20140707134137.GK1803@calimero.vinschen.de> <53BD7161.5030209@acm.org> <20140709170321.GA9946@calimero.vinschen.de> In-Reply-To: <20140709170321.GA9946@calimero.vinschen.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Reply-To: cygwin@cygwin.com X-SW-Source: 2014-07/txt/msg00119.txt.bz2 Corinna Vinschen wrote: > On Jul 9 09:44, David Rothenberger wrote: >> Corinna Vinschen wrote: >>> On Jul 7 12:10, Corinna Vinschen wrote: >>>> On Jul 7 07:28, jojelino wrote: >>>>> 2008-07-27 Corinna Vinschen >>>>> >>>>> * fhandler_socket.cc (fhandler_socket::send_internal): >>>>> Send never more then 64K bytes at once. For blocking >>>>> sockets, loop until entire data has been sent or an error >>>>> occurs. (fhandler_socket::sendto): Drop code which sends on >>>>> 64K bytes. (fhandler_socket::sendmsg): Ditto. >>>>> >>>>> This commit added workaround for KB823764. but it has >>>>> brought another performance issue when writev sends <64k of >>>>> data. >>>> >>>> That's why the code contains that FIXME comment. If you have >>>> a good idea for simple code to split a message into the >>>> least number of pieces to minimize the number of WsaSendTo >>>> calls... >>> >>> I took a stab at the code and I think the new version improves >>> writing multiple small buffers a lot. In my testing it still >>> works in other scenarios, too, but I would be very grateful if >>> somebody could have a critical look into my code changes as >>> posted in >>> https://cygwin.com/ml/cygwin-cvs/2014-q3/msg00003.html >>> >>> I uploaded a new developer snapshot to >>> http://cygwin.com/snapshots/ Please give it a thorough try. >> >> FWIW, this snapshot fixed a recent performance degradation for me >> when doing ssh/rsync transfers within my local network at work. >> These transfers had run at about 25 MB/s but recently degraded to >> about 500 kB/s. The snapshot restored the original performance. > > Cool. Is the result still intact? It's kind of simple to have > lots of performance if the code just doesn't send everything... :} Details, details. :) Yeah, I just tried a transfer and verified the checksum of the transferred file. It worked fine. -- David Rothenberger ---- daveroth@acm.org Hempstone's Question: If you have to travel on the Titanic, why not go first class? -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple