Slow data transfer DS1054Z (python ds1054z)

[Flash375]

I am having trouble transferring data of ds1054z scope to the PC via LAN. Data transfer of 24Mpts takes around 30 min.
I am using python and ds1054z "package" (code is attached). If i transfer BYTES instead of ASCII, transfer time isn't much better (cca. 1sec better on 1.2M samples).

Transfer times for different number of samples are:
Memory depth : 12k   ->   Transfer time:1.48s
Memory depth : 120k  ->  Transfer time:8.48s
Memory depth : 1.2M  ->  Transfer time:83.62s


Does anybody have an idea what is the reason for such long transfer times?

Specs:
Win 10
Python 3.11.1
DS1054z -> Lan cable -> LAN/USB adapter (IB-LAN100-C3)-> PC

[alm]

Try setting the socket options for the TCP/IP connection to the DS1054Z so TCPIP_NODELAY is on: https://www.eevblog.com/forum/testgear/download-speed-from-rigol-ds1054z-or-similar-oscilloscope-to-a-pc/msg4528943/#msg4528943. There appears to be a bug in the DS1054Z TCP/IP stack that causes really bad performance unless the NODELAY socket option is set.

[Flash375]

Thank you for your answer and link. It didn't solve my problem, but gonna read thru linked topic for additional info.

[alm]

The exact syntax to set the NODELAY flag will be somewhat different, I imagine. Let me know if you need help with that, and I'll take a look at how to do that with ds1054z.py.

[Flash375]

Thank you for your offer. I would be glad if you could help me.
So far I have tried to add line to the tcpip.py as suggested by the post (sent link)

Code: [Select]

self._set_tcpip_nodelay(constants.VI_ATTR_TCPIP_NODELAY, True)

I added the line of code to the end of _connect(self) -> StatusCode definition, because it didn't do anything I added the line after line 840, as also suggested by the post. In both cases the transfer is slow.
           

[RoGeorge]

At some point (2015) I've bumped into a similar problem with Windows 10.  The only workaround I could find was to use Linux.  About 1-2 years later, the Win10 problem was fixed, no idea by what update exactly.
https://hackaday.io/project/5807-driverless-rigol-ds1054z-screen-capture-over-lan/log/18807-solved-a-painfully-slow-lan-on-windows-and-a-wasted-weekend

My point is, a Win10 update might fix the slow speed dl. from DS1054Z.

There are ready made Windows tools that are supposed to work with LXI, maybe one of these https://alternativeto.net/software/dsremote/, don't know which one to recommend for Windows.  Installing NI-VISA, or alike free VISA libraries might help.

My advice would be to use Linux and 'PyVISA' or 'lxilib' if you have to download data from Python, or Linux and DSremote if you just want a program to download the data for you as fast as possible.

I don't use Windows since many years ago, so I can not help you with the PM questions you sent me, or any other Windows related questions, sorry. 

[alm]

Thank you for your offer. I would be glad if you could help me.
So far I have tried to add line to the tcpip.py as suggested by the post (sent link)

You are using the DS1054Z module, which uses python-vxi11, right? Which tcpip.py did you modify?

To modify the TCPIP flags as used by Python-VXI11, you'd probably need something like:

Code: [Select]

import socket

ds1054z = DS1054Z(...)
ds1054z.client.sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)

But also note RoGeorge's point about possible issues with Windows. I don't know anything about that.

[Fungus]

I can't imagine the NODELAY flag has any effect on a receiving device.

NODELAY only changes the way packets are assembled on a sending device.

https://en.wikipedia.org/wiki/Nagle%27s_algorithm

[alm]

You'd have to study a pcap trace with and without TCP_NODELAY to be sure, but my guess is that it somehow affects the timing of the ACKs sent back to the scope, and that the scope has a ridiculously small window size. RoGeorge clearly showed a large difference in the previous thread I linked from my first post in this thread.

[Karel]

/usr/include/netinet/tcp.h

Code: [Select]

/*
 * User-settable options (used with setsockopt).
 */
#define TCP_NODELAY 1  /* Don't delay send to coalesce packets  */


/usr/include/linux/tcp.h

Code: [Select]

/* TCP socket options */
#define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */


https://en.wikipedia.org/wiki/Nagle%27s_algorithm

[Fungus]

You'd have to study a pcap trace with and without TCP_NODELAY to be sure, but my guess is that it somehow affects the timing of the ACKs sent back to the scope, and that the scope has a ridiculously small window size. RoGeorge clearly showed a large difference in the previous thread I linked from my first post in this thread.

I guess it could have an effect if there's some sort of very weird bug in the Windows IP code but that seems very unlikely given the number of people hammering on it every day.

It's not something to do with NODELAY per. se. though.

[Flash375]

I am using this https://pypi.org/project/ds1054z/ "library" . I don't know it this library uses python-vxi11 (I am kind of new to python).
Suggestion from the post was, that one should change file tcpip.py which is located in pyvisa_py folder (\AppData\Roaming\Python\Python311\site-packages\pyvisa_py)

I added the line as suggested by you (code bellow) but the speed isn't any better (cca. 8,7s for 120kPts) 

Code: [Select]

from ds1054z import DS1054Z
import time
import socket

#Input IP adress of scope (Manually: Scope->Utility->IO settings-> LAN Conf.)
scope = DS1054Z('169.254.14.84')
#Added line from EEV forum
scope.client.sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
#Print scope idn to verify connection
print("Connected to: ", scope.idn)