Re: Network Performance?
- Date: Sat, 24 Mar 2018 17:04:00 -0700
- From: L A Walsh <cygwin@xxxxxxxxx>
- Subject: Re: Network Performance?
L A Walsh wrote:
What is more important? testing cygwin's scp/sftp/rsync,
or using 'ssh'
or running under cygwin,
or transferring the file to a local backup server from a windows
Jordan Geoghegan wrote:
Has anyone ever successfully transferred 150Mbps or more over the
network using scp/sftp/rsync etc on Cygwin?
client as fast as possible?
Some test notes below(been benching my win<->server
speeds since Win98 days)...
Using bs=16.0M, count=64, iosize=1.0G
R:1073741824 bytes (1.0GB) copied, 1.66724 s, 614MB/s
W:1073741824 bytes (1.0GB) copied, 3.48363 s, 294MB/s
Some additional notes..."/h" is my home directory on the
linux server, so 'bin/iotest is a script in my linux home dir.
The speeds / values using 'Bytes', (2**3) use the base2
prefixes for consistency. To get values in mbits, multiple
The above test only tests transfer speed -- not file i/o --
it uses /dev/zero for a source and /dev/null for a target.
To simplify testing, I created devices 'zero' and 'null'
in my home directory:
ll zero null
crwxrw-rw- 1 1, 3 May 20 2016 null
crw-rw-rw- 1 1, 5 Jun 15 2015 zero
/h> ll zero null
-rwxrw-rw- 1 0 May 20 2016 null*
-rw-rw-rw- 1 0 Jun 15 2015 zero
For write, I used cygwin's 'dd' with if=/dev/zero and of=/h/null.
For read, I used if=/h/zero and of=/dev/null.
Flags for reading: iflag=fullblock conv=nocreat
and for writing: oflag=direct iflag=fullblock conv=nocreat,notrunc
To test the cpu-bounding, I just tried limiting the clock speeds
on the client and server.
Limiting the linux-server's max cpu-speed had
the most affect on performance:
(limited to 1.6GHz instead of 2.4GHz) (33% limitation)
Using bs=16.0M, count=256, iosize=4.0G (~35% slowdown)
R:4294967296 bytes (4.0GB) copied, 10.4467 s, 392MB/s
W:4294967296 bytes (4.0GB) copied, 21.5026 s, 190MB/s
Limiting the client (cygwin-win7sp1x64): (~7-13% slowdown)
(clock limited to 1.16GHz instead of 3.2)
Using bs=16.0M, count=256, iosize=4.0G
R:4294967296 bytes (4.0GB) copied, 7.14355 s, 573MB/s
W:4294967296 bytes (4.0GB) copied, 15.9781 s, 256MB/s
This would indicate that even in the unencrypted case
network transfer speed is cpu bound (and this is using
Problem reports: http://cygwin.com/problems.html
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple