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

[Corinna Vinschen]

On Aug 31 17:52, Takashi Yano wrote:
> On Mon, 30 Aug 2021 17:19:44 +0200
> Corinna Vinschen wrote:
> > On Aug 30 11:00, Ken Brown wrote:
> > > On 8/30/2021 9:51 AM, Ken Brown wrote:
> > > > On 8/30/2021 8:55 AM, Corinna Vinschen wrote:
> > > > > On Aug 30 21:04, Takashi Yano wrote:
> > > > > No worries.  The same should apply to the NtCreateFile side of the
> > > > > pipe, btw.
> > > > 
> > > > I'll add my thanks.  I should have checked the default flags that are
> > > > typically used for other devices when I wrote nt_create.  I'm glad you
> > > > caught this.
> > > > 
> > > > So I'll reinstate the use of nt_create and then let Takashi recheck everything.
> > > 
> > > I've done this now.  I'm still not sure I've got all the flags right.  For
> > > unknown reasons, I've used FILE_SHARE_READ | FILE_SHARE_WRITE in the call to
> > > NtCreateNamedPipeFile, and no sharing in the call to NtOpenFile.  Should I
> > > also use FILE_SHARE_READ | FILE_SHARE in NtOpenFile?  Is sharing even
> > > relevant in this context?
> > 
> > This is only relevant if you want to open the pipe from another context,
> > calling CreateNamedPipe/CreateFile.  As long as the pipe is only
> > duplicated, it shouldn't matter at all.
> > 
> > But, as I just wrote in my previous mail, the FILE_SYNCHRONOUS_IO_NONALERT
> > flag is probably a good thing for C# apps, but not for Cygwin, because it
> > enforces synchronous operation.  Sorry about that...
> 
> With FILE_SYNCHRONOUS_IO_NONALERT, what kind of problems are you
> specifically concerned about cygwin pipe? 

We're using asynchronous IO to be able to call WFMO and thus to be able
to handle signals and thread cancellation events.  Wit hsynchronous IO
this is not possible.


Corinna