apache2 threads w/ 512K stack (default linux 8MB) + wsgi

httpd.conf

# apache2 config tuning for linux (8MB default stack size)
# allows to run more threads, min stack size should depend on worse case scenario
#

#MaxClients 1000
#ThreadsPerChild 64
#MinSpareThreads 500
# default linux 8MB
#ThreadStackSize  8388608
#ThreadStackSize  4194304
#ThreadStackSize  2097152
#ThreadStackSize  1048576
# minimum working for me 512K
ThreadStackSize  524288

# 2 processes (or 2*num_cores+1) to handle reloading (due to maximum-requests).
WSGIDaemonProcess processname user=apache group=apache processes=2 threads=50 stack-size=524288 maximum-requests=500

wsgi.py

# wsgi handler config.
#
#

import thread
#thread.stack_size(8*1024*1024)
#thread.stack_size(4*1024*1024)
#thread.stack_size(2*1024*1024)
#thread.stack_size(1*1024*1024)
thread.stack_size(512*1024)

# e.g. django
# import django.core.handlers.wsgi
# application = django.core.handlers.wsgi.WSGIHandler()