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

Corinna Vinschen corinna-cygwin@cygwin.com
Wed Sep 8 09:01:52 GMT 2021


On Sep  8 13:11, Takashi Yano wrote:
> On Wed, 8 Sep 2021 09:07:48 +0900
> Takashi Yano wrote:
> > On Tue, 7 Sep 2021 19:50:23 +0900
> > Takashi Yano wrote:
> > 
> > > @@ -796,7 +792,8 @@ pipe_cleanup (select_record *, select_stuff *stuff)
> > >        pi->stop_thread = true;
> > >        SetEvent (pi->bye);
> >          ~~~~~~~~~~~~~~~~~~~
> > This is not correct. SetEvent() wakes-up one of thread_pipe()s,
> > but it may be other thread than one which should be stopped.
> > 
> > >        pi->thread->detach ();
> > > -      CloseHandle (pi->bye);
> > > +      if (me->fh->get_select_evt () == NULL)
> > > +	CloseHandle (pi->bye);
> > >      }
> > >    delete pi;
> > >    stuff->device_specific_pipe = NULL;
> > 
> > I think it also should be
> > > +    for (ULONG i = 0; i < get_obj_handle_count (select_evt); i++)
> > > +      SetEvent (select_evt);
> > 
> > Actually I want to use PulseEvent() here if it is not **UNRELIABLE**.
> > https://docs.microsoft.com/en-us/windows-hardware/drivers/devtest/28648-pulseevent-is-an-unreliable-function
> > 
> > Does using semaphore object instead of event, and releasing
> > resources equal to the number of handles make sense?
> 
> No it does not. One thread may consume semaphore multiple times....

What exactly is the problem in the code which results in high CPU
load?  Can you explain this a bit?  Maybe we need an entirely
different approach to avoid that.


Corinna


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