cygrunsrv + sshd + rsync = 20 times too slow -- throttled?

[Corinna Vinschen]

[Moving discussion to cygwin-developers where it belongs]

On Aug 29 18:42, Ken Brown via Cygwin wrote:
> On 8/29/2021 4:41 AM, Takashi Yano wrote:
> > Hi Ken,
> > 
> > On Sat, 28 Aug 2021 16:55:52 -0400
> > Ken Brown wrote:
> > > On 8/28/2021 11:43 AM, Takashi Yano via Cygwin wrote:
> > > > On Sat, 28 Aug 2021 13:58:08 +0200
> > > > Corinna Vinschen wrote:
> > > > > On Aug 28 18:41, Takashi Yano via Cygwin wrote:
> > > > > > On Sat, 28 Aug 2021 10:43:27 +0200
> > > > > > Corinna Vinschen wrote:
> > > > > > > [...]
> > > > > > 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.
> > > > 
> > > > Do you mean, PIPE_NOWAIT flag? If this flags is specified in
> > > > the read pipe, non-cygwin apps cannot read the pipe correctly.
> > > 
> > > While waiting for Corinna's response to this, I have one more question.  Do you
> > > understand why nt_create() failed and you had to revert to create()?  Was it an
> > > access problem because nt_create requested FILE_WRITE_ATTRIBUTES?  Or did I make
> > > some careless mistake in writing nt_create?
> > 
> > I am sorry but no. I don't understand why piping C# program via
> > the pipe created by nt_create() has the issue. I tried to change
> > setup parameters in nt_create(), however, I did not succeed it to
> > work. I also couldn't find any mistake in nt_create() so far.
> > 
> > Win32 programs which use ReadFile() and WriteFile() work even
> > with the pipe created by nt_create() as well as overlapped I/O.
> > 
> > What does C# program differ from legacy win32 program at all?
> 
> I don't know.
> 
> By the way, when I introduced nt_create(), my preference would have been to
> simply change create() to use the NT API, but I was afraid to do that
> because I didn't want to take a chance on breaking something.  That's still
> my preference, if we can find a way to work around this problem with C#
> programs.

Maybe Procmon from sysinternals helps to find the difference in the
working vs. the non-working calls...?


Corinna