From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32225 invoked by alias); 9 Jul 2014 17:03:32 -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 32150 invoked by uid 89); 9 Jul 2014 17:03:28 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-5.9 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=3.3.2 X-HELO: calimero.vinschen.de Received: from aquarius.hirmke.de (HELO calimero.vinschen.de) (217.91.18.234) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 09 Jul 2014 17:03:23 +0000 Received: by calimero.vinschen.de (Postfix, from userid 500) id 785CC8E14EC; Wed, 9 Jul 2014 19:03:21 +0200 (CEST) Date: Wed, 09 Jul 2014 17:03:00 -0000 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: Severe performance degradation of writev Message-ID: <20140709170321.GA9946@calimero.vinschen.de> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <20140707101049.GI1803@calimero.vinschen.de> <20140707134137.GK1803@calimero.vinschen.de> <53BD7161.5030209@acm.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="yrj/dFKFPuw6o+aM" Content-Disposition: inline In-Reply-To: <53BD7161.5030209@acm.org> User-Agent: Mutt/1.5.23 (2014-03-12) X-SW-Source: 2014-07/txt/msg00118.txt.bz2 --yrj/dFKFPuw6o+aM Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Content-length: 1897 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 > >>>=20 > >>> * 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.=20 > >>> (fhandler_socket::sendto): Drop code which sends on 64K bytes.=20 > >>> (fhandler_socket::sendmsg): Ditto. > >>>=20 > >>> This commit added workaround for KB823764. but it has brought > >>> another performance issue when writev sends <64k of data. > >>=20 > >> 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... > >=20 > > 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=20 > > https://cygwin.com/ml/cygwin-cvs/2014-q3/msg00003.html > >=20 > > I uploaded a new developer snapshot to > > http://cygwin.com/snapshots/ Please give it a thorough try. >=20 > 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... :} Corinna --=20 Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Maintainer cygwin AT cygwin DOT com Red Hat --yrj/dFKFPuw6o+aM Content-Type: application/pgp-signature Content-length: 819 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJTvXXZAAoJEPU2Bp2uRE+grcUP/2AX9/1gdb2cC7WAMroFesiC 0KiJo3qiB+cA6u66fy4WNshylFdQQsuJYgjEXOpPyGc8aPv8havAdOVUahZ8Gls8 gdlkilPNQIAhag7vZ+nnVf5bR21MzaFrHTTyFWlVDYKYGbdRDlIhJgxmKEl2wxSm hb/ZHg6G1MyhLtxxw8D6+pEB4KIiKe5qO+FKVPMmuZgpQVs1c1pz+sVJWMG3Bf8q NPeaxw6Bik9OwXsqeWismtMhucykDsPOMdwXoxlw/RHxEUH1qhKGyYu25lD6r4oq +rfaFPjVNjyEzpV0p3+4gff/A4/hudw58gm7v4HKphvxHqPfpZDtcrvJiQ8W+2eA 6x8yAjAtF9fK4M+DkcAuo7PH2iS6Gm4LMmkmR/rQ5tOtnyfYNuZtrNmzJH46vTEr DUPTfAD1nnMLVcUb/lJ1cCD2hm6e2mfv+IYArLDTgK7w5jDZ+MWp2ABzcY3jH0NK Ukr9GR7p/i76QLplA7tvRbTQmDrvFZAA/jvEqjiPLRv/LSJESKByP0BraZt3kExu B+8pgYX5PiYWP8vNFLOimeRTaAmbVeIbf1neh57mveBstYWmvoD7DuXYD4nZSdzR eumsBZawQpfbz1hp+MzsL+VSMTTZiXgZnjM+K9Cd1g1auW4GFdkv7X6Vu+foCmz0 M8+FzY5MsnHj73EDd0QN =Ey44 -----END PGP SIGNATURE----- --yrj/dFKFPuw6o+aM--