Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
Beide Seiten der vorigen RevisionVorhergehende ÜberarbeitungNächste Überarbeitung | Vorhergehende ÜberarbeitungNächste ÜberarbeitungBeide Seiten der Revision | ||
software:linux:realtime:benchmark:start [2019-02-08 16:37] – mgehrig2 | software:linux:realtime:benchmark:start [2019-02-15 11:10] – mgehrig2 | ||
---|---|---|---|
Zeile 23: | Zeile 23: | ||
* BIOS settings | * BIOS settings | ||
* Some drivers, like WiFi driver, may negatively influence latency | * Some drivers, like WiFi driver, may negatively influence latency | ||
+ | |||
+ | ==== Don't ==== | ||
+ | * Don't start the application 'Grub customizer' | ||
+ | |||
+ | |||
+ | ==== Does ==== | ||
+ | * You should remove as many of the unknowns as possible. This means that only the necessary drivers should be loaded. | ||
+ | * If possible, use only a text based system. See ' | ||
+ | * Run only software that is absolutely necessary on the real-time master. | ||
+ | * Deactivate automatic updates. | ||
+ | * A stable system can only be guaranteed if it has been sufficiently tested. Each system is different and must be tested. | ||
+ | |||
===== Methodical procedure ===== | ===== Methodical procedure ===== | ||
Zeile 38: | Zeile 50: | ||
- Test full distro under load | - Test full distro under load | ||
- | ==== Test hardware, BIOS settings and kernel version ==== | + | ==== 1.) Test hardware, BIOS settings and kernel version ==== |
- | - Build a [[software: | + | - Build a [[software: |
- Install the [[software: | - Install the [[software: | ||
- Reboot with the new kernel in [[software: | - Reboot with the new kernel in [[software: | ||
- Check the real-time performance with [[software: | - Check the real-time performance with [[software: | ||
+ | |||
+ | **Tipp**: You may want to use [[https:// | ||
+ | This application provides multiple virtual terminal sessions if you want to run multiple programs in parallel.. | ||
=== Tuning === | === Tuning === | ||
Zeile 49: | Zeile 64: | ||
* Tune some [[software: | * Tune some [[software: | ||
- | * Tune some kernel settings TODO | ||
* Use a different kernel version. (4.4.169-rt177 seems to be better than 4.19.15-rt12) | * Use a different kernel version. (4.4.169-rt177 seems to be better than 4.19.15-rt12) | ||
- | * If the jitter is still to high, you may have to choose a different CPU | + | |
+ | | ||
+ | |||
+ | |||
+ | ==== 2.) Test full distro in text mode ==== | ||
+ | Boot your system in [[software: | ||
+ | |||
+ | If the real-time performance is not significantly reduced, then the third step can be continued. | ||
+ | Run a 24h test so that exceptional events can also be detected. | ||
+ | |||
+ | If the real-time performance is significantly worse, then a WLAN driver or something similar can be the cause. | ||
+ | To further isolate the problem, the WLAN driver, or another suspected driver, can be deactivated ('' | ||
+ | A new test should result in an improvement of the maximum jitter. | ||
+ | |||
+ | === Other possible causes === | ||
+ | * WLAN driver | ||
+ | * Ethernet driver | ||
+ | * Bluetooth driver | ||
+ | * Various peripheral devices | ||
+ | |||
+ | |||
+ | ==== 3.) Test full distro in graphical mode ==== | ||
+ | It is recommended that a real-time system be used only in text mode. | ||
+ | With a graphical user interface, the system is generally more unstable. | ||
+ | |||
+ | If, however, the system is to be used with a graphical user interface, a 24h test [[software: | ||
+ | |||
+ | |||
+ | ==== 4.) Test full distro under load ==== | ||
+ | === High CPU load === | ||
+ | High CPU load from non-RT processes does not affect the performance of RT processes very much. | ||
+ | However, if the processor is not sufficiently cooled (e.g. in a mobile system), the processor can overheat. | ||
+ | In such a case, the processor clock is clocked down by the system, which can severely impair real-time performance. | ||
+ | |||
+ | Check the temperature of the CPU under high load with [[https:// | ||
+ | If the processor does overheat: | ||
+ | * Disable hyper.threading in BIOS | ||
+ | * Deactivate Turboboost in BIOS | ||
+ | * Ensure better cooling | ||
+ | **Note ***: Depending on the processor, // | ||
+ | Observe the // | ||
+ | === Normal Load === | ||
+ | In the last test allplitkation are to be started, which are to run also later in the employment. | ||
+ | For the // | ||
+ | This test should last at least 24 hours. | ||