From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout.easymail.ca (mailout.easymail.ca [64.68.200.34]) by sourceware.org (Postfix) with ESMTPS id C985F3858401 for ; Tue, 24 Aug 2021 19:49:54 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C985F3858401 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=house.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=house.org Received: from localhost (localhost [127.0.0.1]) by mailout.easymail.ca (Postfix) with ESMTP id 2557F8D17E for ; Tue, 24 Aug 2021 19:49:54 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at emo01-pco.easydns.vpn Received: from mailout.easymail.ca ([127.0.0.1]) by localhost (emo01-pco.easydns.vpn [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id B14hG7GupWcA for ; Tue, 24 Aug 2021 19:49:53 +0000 (UTC) Received: from tringa.house.org (S0106bcee7b974edc.gv.shawcable.net [24.108.53.141]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mailout.easymail.ca (Postfix) with ESMTPSA id C3BBC8D179 for ; Tue, 24 Aug 2021 19:49:53 +0000 (UTC) From: Chris Roehrig Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Subject: cygrunsrv + sshd + rsync = 20 times too slow -- throttled? Message-Id: <41A583E1-C8E7-42AB-9F24-EEC33A41EC60@house.org> Date: Tue, 24 Aug 2021 12:49:52 -0700 To: cygwin@cygwin.com Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\)) X-Mailer: Apple Mail (2.1499) X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: cygwin@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: General Cygwin discussions and problem reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Aug 2021 19:49:56 -0000 I have a network of Windows, Linux and Mac machines and I use rsync to = synchronize various directories between them. I'm trying to figure out why my rsync transfers are so slow (<4 MB/s) = only when the remote endpoint is Cygwin rsync over sshd (with both a = Linux or Cygwin rsync client). In all other scenarios, I get the full = 100MB/s as expected from gigabit ethernet. This has been an ongoing = problem for me for a couple of years over several Windows and Cygwin = versions, and I'd like to try to fix it. =20 If I run rsync --daemon --no-detach under mintty in the foreground on = the remote Windows endpoint, I get the full 100 MB/s transfers, so it = seems like it has something to do with rsync.exe running in the = background under the cygrunsrv+sshd service (which was installed = normally using ssh-host-config). If I do: pv /dev/zero | ssh $WINHOST "cat > /dev/null" or even pv /dev/urandom | ssh $WINHOST md5sum I also get the full 100 MB/s transfers, so it doesn't look like sshd = itself is being throttled by bandwidth or CPU. The machines have less than 15% CPU utilization while transferring, with = each of the 4 cores less than 30%, so it doesn't look to be CPU issue. In Task Manager, sshd.exe and rsync.exe seem to be running normally = using only few percent CPU, and show Power Throttling=3DDisabled, = Priority=3DNormal. Setting their Priority to High doesn't seem to = change things. Looking in Resource Monitor on the remote endpoint, the network usage is = pretty much a flat horizontal line at about 18 Mbps (2.5 MB/s), so it = sure looks to me as if rsync is somehow being bandwidth-throttled=08 = when run in the background under cygsshd. It's almost as if rsync has an implicit --bwlimit override when it is = run from cygrunsrv+sshd (I've tried --bwlimit=3D0 on the client which = makes no difference). Any ideas? Not sure where to go from here.=20 Thanks, -- Chris Windows 10 v2004 (64-bit) CYGWIN_NT-10.0 .... 3.2.0(0.340/5/3) 2021-03-29 08:42 x86_64 Cygwin rsync version 3.2.4dev protocol version 31 Linux Mint 20