storescp much slower than scp (copy through ssh)

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martinrame
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Re: storescp much slower than scp (copy through ssh)

#16 Post by martinrame » Mon, 2019-05-13, 19:28

BTW, I built dcmtk with

Code: Select all

cmake . && make
This generates a release or debug version?, if mine is a debug version can it be the cause of the slowness?.

J. Riesmeier
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Re: storescp much slower than scp (copy through ssh)

#17 Post by J. Riesmeier » Mon, 2019-05-13, 19:34

This generates a release or debug version?
I don't know since I (still) prefer GNU Autoconf on Linux systems. You should check this with "ccmake" (which I usually use on Linux when needed).
if mine is a debug version can it be the cause of the slowness?.
I don't think that it slows down the transfer/processing by factor 2 but you should probably check this.

J. Riesmeier
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Re: storescp much slower than scp (copy through ssh)

#18 Post by J. Riesmeier » Mon, 2019-05-13, 19:38

You could also call "cmake -L | fgrep CMAKE_BUILD_TYPE" to see the build type.

martinrame
Posts: 329
Joined: Mon, 2009-02-23, 19:57

Re: storescp much slower than scp (copy through ssh)

#19 Post by martinrame » Mon, 2019-05-13, 20:01

J. Riesmeier wrote:
Mon, 2019-05-13, 19:38
You could also call "cmake -L | fgrep CMAKE_BUILD_TYPE" to see the build type.

Thanks, it returned "CMAKE_BUILD_TYPE:STRING=Release"

martinrame
Posts: 329
Joined: Mon, 2009-02-23, 19:57

Re: storescp much slower than scp (copy through ssh)

#20 Post by martinrame » Tue, 2019-05-14, 16:23

Today I used a Pynetdicom SCP program to test this issue and got the same results (dicom transfer much slower than scp), so it's not a problem of DCMTK.

Anyway, if someone has any idea how to track this issue I'll be glad to hear.

Leonardo.

J. Riesmeier
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Re: storescp much slower than scp (copy through ssh)

#21 Post by J. Riesmeier » Tue, 2019-05-14, 19:52

Did you already check what the maximum throughput of your network connection is (i.e. theoretically). Maybe, your "scp" tool compresses the transferred file by default,

martinrame
Posts: 329
Joined: Mon, 2009-02-23, 19:57

Re: storescp much slower than scp (copy through ssh)

#22 Post by martinrame » Tue, 2019-05-14, 20:03

J. Riesmeier wrote:
Tue, 2019-05-14, 19:52
Did you already check what the maximum throughput of your network connection is (i.e. theoretically). Maybe, your "scp" tool compresses the transferred file by default,
Well, I don't know. How can I check that on Linux (Ubuntu 16.04 Server).

martinrame
Posts: 329
Joined: Mon, 2009-02-23, 19:57

Re: storescp much slower than scp (copy through ssh)

#23 Post by martinrame » Tue, 2019-05-14, 20:08

BTW, I did the test against a virtual machine running on a standard i7 PC on a remote location and it took the same time storescp and scp, so, it looks like the problem is on the Digital Ocean (and Vultr) droplets.

J. Riesmeier
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Re: storescp much slower than scp (copy through ssh)

#24 Post by J. Riesmeier » Wed, 2019-05-15, 09:10

How can I check that on Linux (Ubuntu 16.04 Server).
There are numerous tools. One of them is iperf.

martinrame
Posts: 329
Joined: Mon, 2009-02-23, 19:57

Re: storescp much slower than scp (copy through ssh)

#25 Post by martinrame » Wed, 2019-05-15, 12:21

Ok, using iperf this are the results:

Server:

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------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  4] local BBB.YYY.ZZZ.AAA port 5001 connected with XXX.YYY.ZZZ.AAA port 49134
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-18.6 sec  3.00 MBytes  1.35 Mbits/sec
Client:

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------------------------------------------------------------
Client connecting to BBB.YYY.ZZZ.AAA, TCP port 5001
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  3] local 192.168.0.104 port 49134 connected with BBB.YYY.ZZZ.AAA port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-11.3 sec  3.00 MBytes  2.23 Mbits/sec
I don't know why [ 3] and [ 4} differ (1.35mbits/sec and 2.23mbits/sec), but anyway copying the file with scp gives similar results, and using dcmsend/storescp takes twice as long.

martinrame
Posts: 329
Joined: Mon, 2009-02-23, 19:57

Re: storescp much slower than scp (copy through ssh)

#26 Post by martinrame » Mon, 2019-05-20, 01:09

Today I did a comparison between storescp 3.6.4 and storescp 3.5.4 and found the older is much slower than the newer, almost 10 seconds slower.

All tests performed between my laptop at home sending a file to the Digital Ocean's droplet.

J. Riesmeier
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Re: storescp much slower than scp (copy through ssh)

#27 Post by J. Riesmeier » Mon, 2019-05-20, 09:42

This is what I've meant in my first posting: use the latest version of the DCMTK tools. We've changed a few things in the networking module "dcmnet", which should enhance the performance on recent Linux systems (e.g. don't disable Nagle algorithm and don't set TCP send/receive buffer length by default).

martinrame
Posts: 329
Joined: Mon, 2009-02-23, 19:57

Re: storescp much slower than scp (copy through ssh)

#28 Post by martinrame » Mon, 2019-05-20, 12:18

Apart from this today I installed Conquest, but got the same results, so, aparently the problem is not server side?,

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