reproduce.py

#!/usr/bin/env python

import neovim
import time
import re
import subprocess


def memory_of(pid):
    file = open('/proc/{}/status'.format(pid), 'r')
    mem = re.search('VmRSS:\s+(\d+)', file.read())
    return int(mem.group(1)) / 1024.0


pid = int(subprocess.check_output(['pidof', 'gnome-terminal-server']))
start_mem = memory_of(pid)
nvim = neovim.attach('tcp', address='127.0.0.1', port='9999')

nvim.command('edit $VIMRUNTIME/syntax/ruby.vim')
nvim.command('set foldlevel=20')
nvim.command('100')

nvim.command('vnew $VIMRUNTIME/syntax/css.vim')
nvim.command('set foldlevel=20')
nvim.command('300')

nvim.command('tabnew $VIMRUNTIME/syntax/python.vim')
nvim.command('set foldlevel=20')
nvim.command('300')

for i in range(100):
    nvim.command('tabnext')
    time.sleep(0.2)

nvim.quit()

mem_increase = memory_of(pid) - start_mem

print("Memory start: {} MB".format(start_mem))
print("Memory increase: {} MB".format(mem_increase))

reproduce.vim

set number
set termguicolors
syntax on
color desert