Django WSGI daemon mode synchronization of requests

Running appache2 with the following /etc/httpd.conf:

<VirtualHost *:80>
    WSGIDaemonProcess myapp user=pq group=pq processes=2 threads=1
    WSGIProcessGroup myapp
    LogLevel debug

    <Directory /django/myapp/apache/>
        Order allow,deny
        Allow from all
    </Directory>

    WSGIScriptAlias / /django/myapp/apache/django.wsgi
</VirtualHost>

where this is my /django/myapp/apache/django.wsgi:

import os
import sys

sys.path.append('/django')
os.environ['PYTHONPATH'] = '/django'
os.environ['DJANGO_SETTINGS_MODULE'] = 'myapp.settings'

import django.core.handlers.wsgi
application = django.core.handlers.wsgi.WSGIHandler()

I have the following view:

def sleep(request):
    print >> sys.stderr, '{', os.getpid()
    time.sleep(5)
    print >> sys.stderr, '}', os.getpid()
    return index(request)

I make 4 concurrent requests and my error log shows:

[Wed Jan 12 12:59:56 2011] [error] {17160
[Wed Jan 12 13:00:01 2011] [error] }17160
[Wed Jan 12 13:00:01 2011] [error] {17157
[Wed Jan 12 13:00:06 2011] [error] }17157
[Wed Jan 12 13:00:06 2011] [error] {17160
[Wed Jan 12 13:00:11 2011] [error] }17160
[W开发者_高级运维ed Jan 12 13:00:11 2011] [error] {17157
[Wed Jan 12 13:00:16 2011] [error] }17157

Basically my requests were synchronized per webserver (not even per process).

Why is this?

Edit: This is a single CPU machine and Apache2 is compiled with prefork MMP. My client was 4 tabs in Chrome. Interesting, when I try this with curl I get the expected:

[Wed Jan 12 18:10:18 2011] [error] {17160
[Wed Jan 12 18:10:18 2011] [error] {17157
[Wed Jan 12 18:10:23 2011] [error] }17160
[Wed Jan 12 18:10:23 2011] [error] {17160
[Wed Jan 12 18:10:23 2011] [error] }17157
[Wed Jan 12 18:10:23 2011] [error] {17157
[Wed Jan 12 18:10:28 2011] [error] }17160
[Wed Jan 12 18:10:28 2011] [error] }17157

Edit2: Looks like this is an issue with Chrome synchronizing requests. My (limited) tests showed that this only happens with Chrome and only when tabs are used. Multiple requests within a single tab are asynchronous.