Hi Michael, I tried the 5.15.6 version with my BTLE device, and I can't reproduce it locally. I see a peak on one core when I establish connection to the device and query all the services (my device has 14 services). But reading characteristics takes only about 50% of one core (one of the services has 9 characteristics, so it's comparable to your situation).
Recently we did some improvements and refactoring for the Bluetooth LE connection and service discovery process. You can find some related changes in https://bugreports.qt.io/browse/QTBUG-80719, https://bugreports.qt.io/browse/QTBUG-83633 and https://bugreports.qt.io/browse/QTBUG-96057 You can try the latest patches and see if it improves the situation for you. I'd also encourage you to create a simple non-gui application, just to eliminate the other CPU-consuming factors. It shouldn't be a problem, considering that you know your device's bluetooth address. If you still see high CPU load, feel free to submit a bugreport, providing some more information about your hardware and the minimal reproducer. Best regards, Ivan Solovev Senior Software Engineer The Qt Company Erich-Thilo-Str. 10 12489 Berlin, Germany www.qt.io<http://www.qt.io> Geschäftsführer: Mika Pälsi, Juha Varelius, Jouni Lintunen Sitz der Gesellschaft: Berlin, Registergericht: Amtsgericht Charlottenburg, HRB 144331 B ________________________________ From: Interest <interest-boun...@qt-project.org> on behalf of Michael Heiser | SYSTRONIK Elektronik und Systemtechnik GmbH <hei...@systronik.de> Sent: Thursday, October 7, 2021 7:46 AM To: interest@qt-project.org <interest@qt-project.org> Subject: [Interest] Problems with Qt 5.15.6 on windows when discovering details of a Bluetooth LE service Hello Specialists, I have problems regarding crashes or application hangs on windows 10 with QT 5.15.6 and Bluetooth LE and our own peripherals. We have investigated this on old and also on newer pc hardware. When doing a lowEnergyService discoverDetails() the CPU on each core goes for seconds to 100% which could cause a deadlock in our app on old hardware. On newer hardware the process of discoverDetails() goes often good. After the connect and the service discovery on our bluetooth peripheral with lowenergyscanner when clicking on the service I can reproduce the high CPU load. It needs about 5 seconds to query all the Characteristics of the service, while querying the CPU load is that high on all cores. By the way we have in this specifical BLE service 13 characteristics and before reading the characteristics of this custom service we query DeviceInformation service with 9 characteristics. With Qt 5.12 the query of the same service of our peripheral was okay. So what do you suggest to do? I need to go on with Qt 5.15.6 because we have to launch a recent update on Android within the same code base and I have already made the necessary changes to QML files. Android and IOS by the way are working super. Do you have any advice how to go on? What I definitely not want is to have two source bases Qt 5.15.6 for mobile and Qt 5.12.11 for Windows. Mit freundlichen Grüßen | With best regards Michael Heiser Softwareentwicklung Phone: +49 (0) 7558 / 9206-53 Email: hei...@systronik.de<mailto:hei...@systronik.de> Web: www.systronik.com<http://www.systronik.com/> [cid:image001.png@01D7BB4F.489D5540]<https://www.systronik.com/products/0004000330> SYSTRONIK Elektronik u. Systemtechnik GmbH, Gewerbestr. 57, D-88636 Illmensee Registergericht Ulm - HRB 710423, Sitz der Gesellschaft Illmensee, USt-IdNr. DE 811 264 405 Geschäftsführer: Dipl.-VW Elmar Fritz, Ing. Ramon J. van Tuijl, Dipl.-Ing. (FH) Richard Skoberla Diese E-Mail enthält vertrauliche und/oder rechtlich geschützte Informationen. Wenn Sie nicht der richtige Adressat sind oder die E-Mail irrtümlich erhalten haben, informieren Sie bitte sofort den Absender und löschen Sie die E-Mail. Das unerlaubte Kopieren sowie die unbefugte Weitergabe der E-Mail ist nicht gestattet. This e-mail may contain confidential and / or privileged information. If you are not the intended recipient or the e-mail may contain error, inform you immediately ask the sender and delete the e-mail. Unauthorized copying, unauthorized disclosure of e-mail is strictly forbidden.
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