From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.126.187]) by sourceware.org (Postfix) with ESMTPS id 409743858435 for ; Sat, 28 Aug 2021 11:58:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 409743858435 Received: from calimero.vinschen.de ([24.134.7.25]) by mrelayeu.kundenserver.de (mreue010 [212.227.15.167]) with ESMTPSA (Nemesis) id 1MKsWr-1manXQ1VO9-00LBJY for ; Sat, 28 Aug 2021 13:58:09 +0200 Received: by calimero.vinschen.de (Postfix, from userid 500) id 99DB4A80DDC; Sat, 28 Aug 2021 13:58:08 +0200 (CEST) Date: Sat, 28 Aug 2021 13:58:08 +0200 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: cygrunsrv + sshd + rsync = 20 times too slow -- throttled? Message-ID: Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <20210825201845.07b6400b79dc5558a7761efe@nifty.ne.jp> <20210826062934.54f2f2216021c095bb7ba13b@nifty.ne.jp> <3b560051-ab27-f392-ca4b-d1fd9b5733b0@cornell.edu> <20210827202440.47706fc2fc07c5e9a1bc0047@nifty.ne.jp> <4f2cb5f3-ce9c-c617-f65f-841a5eca096e@cornell.edu> <20210828022111.91ef5b4ff24f6da9fadb489e@nifty.ne.jp> <20210828184102.f2206a8a9e5fe5cf24bf5e45@nifty.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210828184102.f2206a8a9e5fe5cf24bf5e45@nifty.ne.jp> X-Provags-ID: V03:K1:6g5Jq9FjsQnxzegxlbfV/b6b4QSKUs3irtrKViMcdpE+mq+69y2 I7+bRjOzOf19tkze5HjUJqETJ8qGU0tBVS6IiBtnaGbzpHL4QlcG3S993ltPJaUe4IgGGl+ yxV+nB9NkwaOQPTzPkfycY+y4bZlBtIkjTR//NN3PkfVVUZU5iZDIukvMjG+YsUi4Whawog mya2m2bFZMAkMEhE48znw== X-UI-Out-Filterresults: notjunk:1;V03:K0:DBn3d0aSFkk=:OZygRTW6AJt4f9wZf6Q5v8 7CuSeV5oCYOnn3ci98lUN8JWN4F2j6El6Hp5+hcIun82WrMelq+ycfg8MM4NCNL37fK5Whfyp K9T5SaL3xQ9P5i3yQM2w9BndY+idLGl/hGUXyvVAFgB4F8S+fc5Th5QbEPSsHrfJAZxHlKfZ2 o8iRj93T1XNPtg7OPmC7dArD1lsGZEWcECF6rPQmBsnjme+bmWuyoDVYkYC3T4eQNDzr55Ru0 HHDXmpvfZ6+aICOnom5Z8cKur6hq2Sk93Pk7x53EdDSJU7kkEGZJOnS4wc+W6q68inxtcmV5n 8bEMJsazyLzVwDeyCgNWcR1Qq84tEvC/OeEq/6ZSzSmx0MGYwIo7ptFXzMpyBDKNe/ScqsQ62 ATPowrjqNMFtDsXikhxUhXyB2Mxioy1xwAwVEK9OpakbvxcT1MwmX10zUFaC76R0wNW9fY1ec a//8rhpRofzo/o2IiNpVC6GyZJYcnoRE2UJgmNAAG7699RzYDx9AJh+4Kk+iS9E7PI4pbZbGG gSCEklktJeil+XGOgskYU2AnrH7ANQYke+xyvPnn+MkDoozE6wrBX7vhdX4JL/HnLbv3YROfU X2IejBO5LHUIPTMoVTPWSVzg5svpyNxJmog0/0kugqHLIaPLkb2A3Ojp3To0ZSCsDJYihoXxl LZxnNdnVhQ4ykYPMoZQZIQOIfV+t770ClWIBC1xWNbPIsnFJ6eYPAhnZgOPcwN94XWvtzTuHA jYb/DR8TwPbE48XR/iBQh+ccRN6wlZY0BY/ykSKK2iYrIfqddoJ47uwVaIY= X-Spam-Status: No, score=-99.8 required=5.0 tests=BAYES_00, GOOD_FROM_CORINNA_CYGWIN, JMQ_SPF_NEUTRAL, KAM_DMARC_NONE, KAM_DMARC_STATUS, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NEUTRAL, TXREP 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: Sat, 28 Aug 2021 11:58:21 -0000 On Aug 28 18:41, Takashi Yano via Cygwin wrote: > On Sat, 28 Aug 2021 10:43:27 +0200 > Corinna Vinschen wrote: > > On Aug 28 02:21, Takashi Yano via Cygwin wrote: > > > On Fri, 27 Aug 2021 12:00:50 -0400 > > > Ken Brown wrote: > > > > Two years ago I thought I needed nt_create to avoid problems when calling > > > > set_pipe_non_blocking. Are you saying that's not an issue? Is > > > > set_pipe_non_blocking unnecessary? Is that the point of your modification to > > > > raw_read? > > > > > > Yes. Instead of making windows read function itself non-blocking, > > > it is possible to check if the pipe can be read before read using > > > PeekNamedPipe(). If the pipe cannot be read right now, EAGAIN is > > > returned. > > > > The problem is this: > > > > if (PeekNamedPipe()) > > ReadFile(blocking); > > > > is not atomic. I. e., if PeekNamedPipe succeeds, nothing keeps another > > thread from draining the pipe between the PeekNamedPipe and the ReadFile > > call. And as soon as ReadFile runs, it hangs indefinitely and we can't > > stop it via a signal. > > Hmm, you are right. Mutex guard seems to be necessary like pty code > if we go this way. > > > Is a blocking ReadFile actually faster than a non-blocking read? Or > > does it mainly depend on BYTE vs. MESSAGE mode? > > Actually, I don't think so. Perhaps it is not essential problem of > overlapped I/O but something is wrong with current pipe code. > > > What if the pipe is created non-blocking and stays non-blocking all the > > time and uses BYTE mode all the time? Just as sockets, it would always > > only emulate blocking mode. Wouldn't that drop code size a lot and fix > > most problems? > > If 'non-blocking' means overlapped I/O, only the problem will be: > https://cygwin.com/pipermail/cygwin/2021-March/247987.html Sorry if that wasn't clear, but I was not talking about overlapped I/O, which we should get rid off, but of real non-blocking mode, which Windows pipes are fortunately capable of. Corinna