Hi
The first part of the enquiry sounds like a benchmark. There are all kinds of benchmarks. But they give the result, well in benchmark units. Not always in the units you would like to have, for example, number of concurrent Moodle users. (Doing what?)
The first part of the enquiry sounds like a benchmark. There are all kinds of benchmarks. But they give the result, well in benchmark units. Not always in the units you would like to have, for example, number of concurrent Moodle users. (Doing what?)
That said, there was one test during the Moodle 1.x times, which gave the result in concurrent users: https://moodle.org/mod/forum/discuss.php?d=57028. Don't ask me the maths behind it. 
There are ways of constructing your own load tests. See https://docs.moodle.org/dev/JMeter. Or for comparisons: Moodle Benchmark https://moodle.org/mod/forum/discuss.php?d=335357 or https://github.com/moodlehq/moodle-performance-comparison.
To get the background of the whole subject, pl. go through the https://docs.moodle.org/en/Performance documentation.
There are ways of constructing your own load tests. See https://docs.moodle.org/dev/JMeter. Or for comparisons: Moodle Benchmark https://moodle.org/mod/forum/discuss.php?d=335357 or https://github.com/moodlehq/moodle-performance-comparison.
To get the background of the whole subject, pl. go through the https://docs.moodle.org/en/Performance documentation.