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 E22293858401 for ; Wed, 25 Aug 2021 00:35:21 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org E22293858401 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 2AE5110D3E9; Wed, 25 Aug 2021 00:35:21 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at emo02-pco.easydns.vpn Received: from mailout.easymail.ca ([127.0.0.1]) by localhost (emo02-pco.easydns.vpn [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id PLL-lHCbCxdu; Wed, 25 Aug 2021 00:35:16 +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 6DC7310D390; Wed, 25 Aug 2021 00:35:16 +0000 (UTC) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\)) Subject: Re: cygrunsrv + sshd + rsync = 20 times too slow -- throttled? From: Chris Roehrig In-Reply-To: Date: Tue, 24 Aug 2021 17:35:15 -0700 Cc: cygwin@cygwin.com Content-Transfer-Encoding: quoted-printable Message-Id: <28B175CC-A653-4279-A683-A4759029DDDD@house.org> References: <41A583E1-C8E7-42AB-9F24-EEC33A41EC60@house.org> To: Mark Geisert 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: Wed, 25 Aug 2021 00:35:32 -0000 Here's my test in a nutshell: # ON WINDOWS: install Cygwin and enable cygsshd ssh-host-config -y # set up authorized keys, etc to make things easier # LINUX: Create a 2GB random file on Linux: dd if=3D/dev/urandom of=3D/tmp/bigfile.bin bs=3D1M count=3D2000 # WINDOWS: rsync "pull" to cygwin LINUXHOST=3Dmylinuxhost rsync -Pva $LINUXHOST:/tmp/bigfile.bin /tmp/ # = 100MB/s full speed rm /tmp/bigfile.bin # LINUX: rsync "push" to cygwin (from Linux machine) WINHOST=3Dmywindowshost rsync -Pva /tmp/bigfile.bin $WINHOST:/tmp/ # slow, = dropping to 4MB/s I get the same results transferring the other direction (WIN -> LINUX): = The Cygwin remote endpoint is always slow. On Tue Aug 24 2021, at 4:43 PM, Mark Geisert wrote: > Chris Roehrig wrote: >> 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. >> 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 > You're not the first to report this. I don't have any quick answer. = But can you give one or two simple examples of commands that give slow = transfers in your environment? Simple like your 'pv' examples, if = possible, using whatever method that works. >=20 > ..mark >=20 > --=20 > Problem reports: https://cygwin.com/problems.html > FAQ: https://cygwin.com/faq/ > Documentation: https://cygwin.com/docs.html > Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple