Here's the other direction with rsync also in --daemon mode:
# ON WINDOWS (from a mintty terminal):
dd if=/dev/urandom of=/tmp/bigfile.bin bs=1M count=2000 # create 2GB
file
printf "[TMP]\npath = /tmp\n" > /etc/rsyncd.conf
# create rsyncd.conf
rsync --daemon --no-detach
# run rsync in daemon mode
# ON LINUX:
rm -f /tmp/bigfile.bin; rsync -Pva $WINHOST:/tmp/bigfile.bin /tmp/
# 4MB/s
rm -f /tmp/bigfile.bin; rsync -Pva rsync://$WINHOST/TMP/bigfile.bin /tmp/
# 100MB/s
I was thinking that there might be some Windows Policy that rate-limits some
syscalls for background process, but I also tried:
# ON WINDOWS (Administrator mintty):
cygrunsrv -E cygsshd # exit sshd service
/usr/sbin/sshd -D # run sshd in
"foreground" (GUI app)
and I still get 4MB/s.
Maybe some IPC rate-limit issue between sshd and rsync (but that isn't there
between e.g. sshd and md5sum... ?)
On Tue Aug 24 2021, at 7:02 PM, NightStrike <nightstr...@gmail.com> wrote:
> Older versions of windows had a setting to optimize the OS for either
> background services or foreground applications. One of the things this did
> was throttle network usage. I don't know if windows 10 has the same setting
> though.
I read about a NetworkThrottlingIndex that limits "non-multimedia" packets to
10 per millisecond which can be disabled by setting:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT\CurrentVersion\Multimedia\SystemProfile]
"NetworkThrottlingIndex"=dword:ffffffff
but this made no difference to my tests.
On Tue Aug 24 2021, at 5:35 PM, Chris Roehrig <croeh...@house.org> wrote:
> Here's my test in a nutshell:
>
> # ON WINDOWS: install Cygwin and enable cygsshd
> ssh-host-config -y
> # set up authorized keys, etc to make things easier
>
> # LINUX: Create a 2GB random file on Linux:
> dd if=/dev/urandom of=/tmp/bigfile.bin bs=1M count=2000
>
> # WINDOWS: rsync "pull" to cygwin
> LINUXHOST=mylinuxhost
> rsync -Pva $LINUXHOST:/tmp/bigfile.bin /tmp/ # 100MB/s full
> speed
> rm /tmp/bigfile.bin
>
> # LINUX: rsync "push" to cygwin (from Linux machine)
> WINHOST=mywindowshost
> rsync -Pva /tmp/bigfile.bin $WINHOST:/tmp/ # slow,
> dropping to 4MB/s
>
>
> I get the same results transferring the other direction (WIN -> LINUX): The
> Cygwin remote endpoint is always slow.
>
>
>
>
>
> On Tue Aug 24 2021, at 4:43 PM, Mark Geisert <m...@maxrnd.com> wrote:
>
>> Chris Roehrig wrote:
>>> I have a network of Windows, Linux and Mac machines and I use rsync to
>>> synchronize various directories between them.
>>> I'm trying to figure out why my rsync transfers are so slow (<4 MB/s) only
>>> when the remote endpoint is Cygwin rsync over sshd (with both a Linux or
>>> Cygwin rsync client). In all other scenarios, I get the full 100MB/s as
>>> expected from gigabit ethernet. This has been an ongoing problem for me
>>> for a couple of years over several Windows and Cygwin versions, and I'd
>>> like to try to fix it.
>>> If I run rsync --daemon --no-detach under mintty in the foreground on the
>>> remote Windows endpoint, I get the full 100 MB/s transfers, so it seems
>>> like it has something to do with rsync.exe running in the background under
>>> the cygrunsrv+sshd service (which was installed normally using
>>> ssh-host-config).
>>> If I do:
>>> pv /dev/zero | ssh $WINHOST "cat > /dev/null"
>>> or even
>>> pv /dev/urandom | ssh $WINHOST md5sum
>>> I also get the full 100 MB/s transfers, so it doesn't look like sshd itself
>>> is being throttled by bandwidth or CPU.
>>> The machines have less than 15% CPU utilization while transferring, with
>>> each of the 4 cores less than 30%, so it doesn't look to be CPU issue.
>>> In Task Manager, sshd.exe and rsync.exe seem to be running normally using
>>> only few percent CPU, and show Power Throttling=Disabled, Priority=Normal.
>>> Setting their Priority to High doesn't seem to change things.
>>> Looking in Resource Monitor on the remote endpoint, the network usage is
>>> pretty much a flat horizontal line at about 18 Mbps (2.5 MB/s), so it sure
>>> looks to me as if rsync is somehow being bandwidth-throttled when run in
>>> the background under cygsshd.
>>> It's almost as if rsync has an implicit --bwlimit override when it is run
>>> from cygrunsrv+sshd (I've tried --bwlimit=0 on the client which makes no
>>> difference).
>>> Any ideas? Not sure where to go from here.
>>
>> You're not the first to report this. I don't have any quick answer. But
>> can you give one or two simple examples of commands that give slow transfers
>> in your environment? Simple like your 'pv' examples, if possible, using
>> whatever method that works.
>>
>> ..mark
>>
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