[erlang-bugs] Erlang 18.0-rc1 is behaving slower than 17.4 (and 17.5)

[Jesper Louis Andersen]

On Mon, Apr 13, 2015 at 6:44 PM, José Valim <jose.valim@REDACTED
> wrote:

> 2. The time to start, write to stdio and shutdown the erlang system is
> higher on 18.0


I was interested in this one, because I think I've perceived startup times
being less regular, and this is a good check. I did:

[jlouis@REDACTED 2]$ for i in $(seq 1 100); do time erl -eval
"io:format(hello, []), halt()." ; done > collected.txt 2>&1
grep real collected.txt | sed -e 's/^.*m//g' -e s/s$//g > data.txt

To collect the necessary data. On a FreeBSD system, you might need the
jot(1) command rather than the seq(1) command, but the idea is the same.

In R:

x <- read.csv('data.txt', header=FALSE)
> summary(x)
       V1
 Min.   :0.1890
 1st Qu.:0.1930
 Median :0.1940
 Mean   :0.1948
 3rd Qu.:0.1963
 Max.   :0.2050

In other words, my hunch was soundly destroyed by data. I've seen what I
perceive to be longer boot times as well, and they seem to deviate more.
But the human perception is so bad at precise measurements. Consider using
the above script-idea together with R to obtain some more data and better
numbers. The mean is usually only a good statistic if you have other data.

-- 
J.
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