On Fri, 27 Aug 2021 12:00:50 -0400 Ken Brown wrote: > On 8/27/2021 7:24 AM, Takashi Yano wrote: > > On Thu, 26 Aug 2021 18:18:29 -0400 > > Ken Brown wrote: > >> On 8/26/2021 11:56 AM, Ken Brown via Cygwin wrote: > [...] > >> In case you want to try out my proposed change, I've just rebased the > >> patches to > >> the current master and pushed them to a new topic/pipe branch. > > > > Hi Ken, > > > > Thanks much! I tested topic/pipe branch. > > > > [yano@cygwin-PC ~]$ scp test.dat yano@linux-server:. > > yano@linux-server's password: > > test.dat 100% 100MB 95.9MB/s 00:01 > > [yano@cygwin-PC ~]$ scp yano@linux-server:test.dat . > > yano@linux-server's password: > > test.dat 100% 100MB 8.0MB/s 00:12 > > > > yano@linux-server:~$ scp yano@cygwin-PC:test.dat . > > yano@cygwin-PC's password: > > test.dat 100% 100MB 109.7MB/s 00:00 > > yano@linux-server:~$ scp test.dat yano@cygwin-PC:. > > yano@cygwin-PC's password: > > test.dat 100% 100MB 31.4MB/s 00:03 > > > > As shown above, outgoing transfer-rate has been improved upto near > > theoretical limit. However, incoming transfer-rate is not improved > > much. > > > > I digged further and found the first patch attached solves the issue > > as follows. > > > > [yano@cygwin-PC ~]$ scp yano@linux-server:test.dat . > > yano@linux-server's password: > > test.dat 100% 100MB 112.8MB/s 00:00 > > > > yano@linux-server2:~$ scp test.dat yano@cygwin-PC:. > > yano@cygwin-PC's password: > > test.dat 100% 100MB 102.5MB/s 00:00 > > Great! > > > I also tested the case: > >>>> https://cygwin.com/pipermail/cygwin/2021-March/247987.html > >>>> which seems to be the same issue with > >>>> https://stackoverflow.com/questions/10385424/good-alternatives-to-cygwin-cygwin-doesnt-support-natively-support-win32-app > > > > Unfortunately, topic/pipe does not help. > > > > I confirmed that applying the second patch attached, which reverts > > to create() rather than nt_create(), and setting CYGWIN=pipe_byte > > fixes the problem. > > > > What do you think of this alternative implementation which does > > not use nt_create()? > > 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. -- Takashi Yano <takashi.y...@nifty.ne.jp> -- 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
