Hi @richard
We have done some follow up tests using a Kolibri RPi (4B+ 4GB RAM) server.
The results were something of a surprise.
It quickly became obvious that we would not be able to get the same level of performance as in the previous tests where we used an i3 laptop as the Kolibri server, so we started with a lower level of load to see what was happening. The following screenshots show the results.
The test set up is essentially the same as previously, with the Kolibri RPi server connected by Ethernet cable to an Access Point to which client laptops connect via WiFi.
The server was running the Koilbri RPi image.
The video files used have been optimised.
- Test Stage 1
Three client laptops connected, each with two browser tabs open and running one of the Entrepreneur videos from Khan Academy (US) channel. Below is a screenshot of the ‘top’ command running on the Kolibri RPi server.
You can see that the Load Average has risen to 4.19 from a value of 0.58 before the test was started.
At this point the Kolibri system is still reasonably responsive to user requests.
The Load Average value slowly reduces over time.
- Test Stage 2.
The load is increased to four browser tabs each running one of the videos.
Below is the ‘top’ command output.
You can see that the load Average value has gone up to 5.25.
At this point the system is becoming fairly unresponsive to user requests and it is effectively not possible to add any further load with extra clients.
- Access Point Performance
The following screenshot shows the output of the ‘top’ command for the OpenWRT Access Point (GLiNet MT300N-V2) for the Stage 2 Test.
You can see that the OpenWrt system is not experiencing any significant load, with a Load Average of 0.04.
- In Summary…
We were surprised with the results. We had expected that the RPi device would have performed similarly to the i3 laptop running Desktop Ubuntu. But in fact the level of performance is much lower, and indicates that the RPi would not service a full classroom of students (which Radina pointed out earlier).
The overall improvement we expected to get from optimising the videos has not resulted in better overall performance (although large non-optimised videos will bring the system to its knees if even one user makes the request).
We don’t understand what is generating the workload on the Kolibri server.
The ‘top’ command shows that the main load is from the kolibri, nginx and uwsgi processes.
None of these seem to be consuming huge amounts of system resources.
We know that just serving the optimised videos doesn’t itself create a great workload as we can serve them directly from a web server (lighttpd) running on the Access Point, and deliver 30 videos concurrently just from the tiny OpenWrt system running on the AP.
So what other workload is consuming the resources on the RPi???
- More investigation required…
Regards
Terry