HOWTO: lightning fast Emacs on Linux multicore

[Emanuel Berg]

A couple of months ago I got a multicore computer.
Better yet, it is a dualcore :)

I thought I'd share a trade-secret for all us
Emacs-only users.

There is a saying that the common case is the one that
should be optimized. That's what I'm doing here, with
the common case being - Emacs.

(This assumes a Debian Linux but I don't think it'd
look that different on other distributions or even
systems.)

First, confirm you have a multicore with

    lscpu | egrep '^CPU\(s\)'

Then, go to

    /etc/default/grub

and, as superuser, insert or change the line with
GRUB_CMDLINE_LINUX_DEFAULT into this:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet isolcpus=1"

Then

    sudo update-grub

and

    shutdown -h now -r # or otherwise reboot

After rebooting

    ps -eo psr,comm | grep ' 1 '

to see that almost no processes are executing on
CPU 1. But life in the vault is about to change...

Launch Emacs like this:

    taskset -c 1 emacs

Now, Emacs has a core to itself and should run much
faster, at least for normal usage.

-- 
underground experts united