[SOLVED] RTT slow not usable anymore

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  • [SOLVED] RTT slow not usable anymore

    We have been using RTT for many years now and since a few months the logging output became so slow that it's unusable.

    I've seen post here with the workaround using a older version of the driver.

    What is the timeline in fixing this issue?

    We already decided not to use RTT with any future projects anymore.
    But we still have to rely on it for the legacy hardware.
  • Hello,

    Thank you for your inquiry.
    Such an issue is not known to us with the latest version.
    Which J-Link software version are you currently using? Does the behaviour improve when using the latest one?

    timurlocumi wrote:

    We have been using RTT for many years now and since a few months the logging output became so slow that it's unusable.
    What tool are you using for logging? Your own, or one of the J-Link tools?

    timurlocumi wrote:

    I've seen post here with the workaround using a older version of the driver.

    What is the timeline in fixing this issue?
    The old reported issues in the forum have all been fixed already.

    timurlocumi wrote:

    We already decided not to use RTT with any future projects anymore.
    May we ask what your alternative solution is?

    Best regards,
    Nino
    Please read the forum rules before posting: Forum Rules

    Keep in mind, this is not a support forum. Its main purpose is user to user interaction.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
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  • I have been using the latest v6.42d and there is still a lot of lag in the RTT viewer compared to say v6.32i

    Actually I ran another test, 6.32i RTT Viewer is about 1000% faster than anything released after that - 6.42d and 6.43a are both hopelessly slow. I assume you are somehow buffering the data before writing it out to the display, whatever you used to do was perfectly adequete. I end up going back and using it even though the DPI support is kinda poor in that version.
  • Hello,

    Thank you for your feedback.
    To investigate this further we would need a reproduction scenario.
    Could you provide us with an example project for some Cortex-M eval board?
    Easiest for us would be for Embedded Studio, but if you use another IDE the output elf file would be sufficient.

    Best regards,
    Nino
    Please read the forum rules before posting: Forum Rules

    Keep in mind, this is not a support forum. Its main purpose is user to user interaction.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support contact us per e-mail.
    Alternatively our support system can be used as well: segger.com/ticket/
  • I had this same problem, see [ABANDONED] RTT Viewer 6.40 slow? (never got a notification from the forum software therefore I had not seen it was answered).
    We noticed the behavior depends on the host machine in use. We had this problem on several laptops and one desktop, all running Windows 10 Pro. In the end, we found a single machine (some HP laptop) where RTT ran sluggish / slow on 2 of the available USB ports but ran fine on a third one. Unfortunately, that specific laptop belongs to a customer and once "fixed" I did not have access to that machine anymore.

    Anyway. The thing I wanted to mention is that the slowness is worst on RTT Viewer, it's slightly better using RTT Logger (yet not good enough by far) and it's okay in SES and oZone. Since we do not use eval boards, I cannot provide an example that is guaranteed to run on a COTS DVL board but hopefully TS can (note: I modified an existing example from Nordic's SDK to show the problem, see below. This should run on PCA10040 too).

    Configuration:
    - tested both, J-Link Pro and iTrace pods connected through USB
    - My own laptop (Lenovo ThinkPad E570) suffers from this issue and so does my desktop (unbranded)
    - Target: Nordic nRF52832, with 32 MHz and 32 kHz crystals
    - The issue is there when our software is compiled with either, IAR EW for ARM v8.11.2 or SES for ARM v3.40
    - Test application for reproduction: Nordic SDK5 v15.2, examples/ble_peripheral/ble_app_uart/pca10040/s132/ses. Changes made in main.c only:
    • Included nrf_delay.h and SEGGER_RTT.h
    • Replaced the main loop in main() to read:

    Source Code

    1. // Enter main loop.
    2. for (;;)
    3. {
    4. static int count = 0;
    5. SEGGER_RTT_printf( 0, "Count = %d\n", count++ );
    6. nrf_delay_us( 10000 ); // Delays roughly 10 msec
    7. // idle_state_handle();
    8. }
    In the SES debugger, the counter runs smoothly. In RTT viewer, the output visibly stutters and misses characters from time to time.

    Edit: the example will run for 3 minutes. Than it'll go into sleep because BLE advertisement times out. You can change this by setting APP_ADV_DURATION to 0 in main.c.

    The post was edited 2 times, last by jev ().

  • Hi,

    little update in this regard.
    In the latest J-Link software version V6.44c the RTT Viewer should be back to old speeds and according to our measurements even faster.

    Could you give it a try and report back your findings?

    Best regards,
    Nino
    Please read the forum rules before posting: Forum Rules

    Keep in mind, this is not a support forum. Its main purpose is user to user interaction.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support contact us per e-mail.
    Alternatively our support system can be used as well: segger.com/ticket/
  • Hi Timur,

    Great to hear that you are up and running again.
    This thread will be marked as solved now.

    Best regards,
    Nino
    Please read the forum rules before posting: Forum Rules

    Keep in mind, this is not a support forum. Its main purpose is user to user interaction.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support contact us per e-mail.
    Alternatively our support system can be used as well: segger.com/ticket/