bug#7069: Clarification

[Lars Hamren]

The problem, as far as I can determine, is not that the compilation
process takes longer, but that buffer/window update is slow.

For long compilations, with output more than a few kB, output is
"chunky". Updates seem to be in multiples of 4 kB, with delays
between them. Running strace supports this assumption.

I tried this as a "compilation":

     time find /path/to/somewhere -ls

With "compile" (slow, chunky buffer update)

        real    0m30.488s
        user    0m0.032s
        sys     0m0.036s

With "shell-command" (immediate buffer update)

        real    0m0.027s
        user    0m0.020s
        sys     0m0.008s

From Bash, not within emacs

        real    0m0.028s
        user    0m0.016s
        sys     0m0.012s

User and system times are effectively the same, but real
time differs by a factor of 1000.

/Lars Hamrén