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Type: Posts; User: ardvark

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    Please ignore my previous post...

    Please ignore my previous post (https://forum.pjrc.com/threads/68386-Teensyduino-1-56-Beta-2?p=290757&viewfull=1#post290757) about throughput slowing down for large transfers. The speed issues were...
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    Well, this is super embarrassing. You are 100%...

    Well, this is super embarrassing. You are 100% correct and I've been chasing my own tail. I stopped storing the data and I can hold 32MBPS throughput for 100's of MB with no slow down. I added...
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    For completeness, here are the same plots, but...

    For completeness, here are the same plots, but tested under Windows. Some data was dropped / corrupted, but I just ignored it. The weird discontinuity at ~5MB is gone, and the rate dropping isn't as...
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    I took a longer data set and there is a sudden...

    I took a longer data set and there is a sudden change in rate at 4.8MB (this number is not consistent shot to shot -- sometimes it happens at 5.5MB for example). I've attached plots on both linear...
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    This is just speculation, but I wonder if once...

    This is just speculation, but I wonder if once some buffer fills up, the Teensy waits until it can send more data, but as soon as it can, it sends a small amount, and then sends another small amount...
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    Ok, sorry, please ignore the previous post's data...

    Ok, sorry, please ignore the previous post's data -- I accident used the wrong data set. Here's data that shows the (somewhat averaged) instantaneous data rate vs Bytes sent for two sends: 0.8MB and...
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    I analyzed the USB packets I posted in...

    I analyzed the USB packets I posted in https://forum.pjrc.com/threads/68386-Teensyduino-1-56-Beta-2?p=290757&viewfull=1#post290757 (not sure if I should be posting here, in the 1-56-Beta-1 thread,...
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    Done....

    Done. https://forum.pjrc.com/threads/68386-Teensyduino-1-56-Beta-2?p=290757#post290757 I also recompiled the Teensy code with the latest 1.56 beta2 firmware, say the same behavior and uploaded new...
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    I hope this is the right place to post -- there...

    I hope this is the right place to post -- there are more details in https://forum.pjrc.com/threads/68382-Serial-write-xmit-dropping-data but I was asked there to post the data here. Basically, I have...
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    I did some more testing, this time with Linux to...

    I did some more testing, this time with Linux to hopefully rule out the Windows comm port bug. Using my latest Teensy code, if I try sends of different size, I get:



    Length of data received:...
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    luni -- That's amazing. I swear I did that same...

    luni -- That's amazing. I swear I did that same test and it didn't work. But I tried your Teensy code with a python script and I'm able to reproduce the same behavior: 30MBPS for each data transmit...
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    Actually, I left it in the whole time: ...

    Actually, I left it in the whole time:



    while ( localWordsToSend != localWordsSent) {
    uint packetSize = min((uint) SENDSIZE,localWordsToSend - localWordsSent);
    while ( (uint)...
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    Actually, I did a test with Linux using PySerial...

    Actually, I did a test with Linux using PySerial and it always showed the same throughput drop with larger transfers and it sometimes showed data loss as well, depending on size of the Serial.write()...
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    I'm going to try to summarize: PySerial +...

    I'm going to try to summarize:

    PySerial + Teensy 4 sees throughput drop drastically for large sends (Windows & Linux)
    PySerial + Teensy 4 sees dropped packets for large sends (Windows & Linux* --...
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    I updated my python script to report how fast the...

    I updated my python script to report how fast the data transfer is and what data points are bad. I ran this script on a Linux machine for different transfer sizes, and I get the following results (no...
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    Small update. When it errors, I updated the...

    Small update. When it errors, I updated the python code to now print how far it got before it ran out of data with the new line

    raise Exception('Error, got only {} bytes, but expecting {},...
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    Thanks for the quick reply. I tried using the...

    Thanks for the quick reply. I tried using the usb_serial.c at the https://github.com/FrankBoesing/cdcbench/blob/main/usb_serial.c, but I still get dropped data. I also added the "dsb" assembly code...
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    Serial.write xmit dropping data

    I have a Teensy 4 and have it collect a bunch of data and then stream it back to the computer over usb via Serial.write(). For small data sets, this works fine, but if I send 100kB or more, I get...
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