[mod_python] how to run multiple subinterpreters from mod_python

Hi Graham,
my libxx makes openssl calls to do some crypto stuff. only a few http
requests land up on that code path.

i made this test...
for a url say, http://myserver/myapp/test. i put sleep in the python handler
code.

//python handler for the above url
{
    import time
    log('before sleep')
    time.sleep(60)
    log('after sleep')
}

when multiple clients access the url, the calls are serialized. the second
client waits for a minute and then comes to this handler.
why is this so? that's why i was lead to believe that the requests were
serialized.

am i missing something in the config?

this is httpd -l output. worker.c is compiled in
Compiled in modules:
  core.c
  mod_authn_file.c
  mod_authn_default.c
  mod_authz_host.c
  mod_authz_groupfile.c
  mod_authz_user.c
  mod_authz_default.c
  mod_auth_basic.c
  mod_auth_digest.c
  mod_include.c
  mod_filter.c
  mod_deflate.c
  mod_log_config.c
  mod_env.c
  mod_expires.c
  mod_setenvif.c
  mod_proxy.c
  mod_proxy_connect.c
  mod_proxy_ftp.c
  mod_proxy_http.c
  mod_proxy_ajp.c
  mod_proxy_balancer.c
  mod_ssl.c
  worker.c
  http_core.c
  mod_mime.c
  mod_status.c
  mod_autoindex.c
  mod_asis.c
  mod_negotiation.c
  mod_dir.c
  mod_actions.c
  mod_userdir.c
  mod_alias.c
  mod_rewrite.c
  mod_so.c

On 1/24/07, Graham Dumpleton <grahamd at dscpl.com.au> wrote:
>
> Suresh Lakshmanan wrote ..
> > Hi Graham,
> > I'm not very familiar with the apache MPM model. Thanks for your
> references,
> > im able to get an idea of how the subinterpreters work in mod_python.
> >
> > My python application is a django based application. It uses a few
> python
> > modules like
> > PIL (python imaging library), dnspython, django, libxx (our c++
> extension
> > written in python)
> >
> > Multiple requests to my django application (running inside apache with
> > mod_python) are serialized and they execute one by one.
> > Lot of them get 503 responses.
> >
> > Here's my apache conf.
>
> Does running:
>
>   httpd -l
>
> actually show worker.c in the list of files. Ie. to confirm that worker
> MPM is
> actually compiled in.
>
> > # worker MPM
> > # StartServers: initial number of server processes to start
> > # MaxClients: maximum number of simultaneous client connections
> > # MinSpareThreads: minimum number of worker threads which are kept spare
> > # MaxSpareThreads: maximum number of worker threads which are kept spare
> > # ThreadsPerChild: constant number of worker threads in each server
> process
> > # MaxRequestsPerChild: maximum number of requests a server process
> serves
> > <IfModule worker.c>
> > StartServers         1
> > MaxClients          64
> > MinSpareThreads     64
> > MaxSpareThreads     64
> > ThreadsPerChild     64
> > MaxRequestsPerChild  0
> > ServerLimit          1
>
> This is what I was talking about with limiting the maximum number of child
> process to 1. Because you have this, if a single request takes some time
> to
> execute and the point it is waiting or taking time in is in C/C++ code in
> a
> external Python module, and that module doesn't properly release the
> Python
> GIL, all other requests will bank up behind that one request waiting for
> it to
> return out of the C/C++ code.
>
> In your libxx module, do you perform things in the C++ code that take a
> while
> or do you make calls to stuff which can block. Do you ensure that you wrap
> time
> consuming operations of code that can block in:
>
>     Py_BEGIN_ALLOW_THREADS
>     ... blocking or time consuming operation.
>     Py_END_ALLOW_THREADS
>
> > </IfModule>
> >
> > <Location "/reg/">
> >     SetEnv PYTHONHOME "/usr/local/bin/python2.4"
>
> This will not actually do anything for mod_python itself. Would only
> affect CGI
> scripts which are written in Python.
>
> >     SetHandler python-program
> >     PythonPath "['/usr/local/pi/applications/',
> > '/usr/local/pi/nodes/data/regist
> > ration', '/usr/local/pi/pimgr/lib', '/usr/local/pi/pimgr/lib/ca' ,
> > '/usr/local/p
> > i/pimgr/lib/MySQLdb'] + sys.path"
> >     PythonHandler django.core.handlers.modpython
> >     SetEnv PINET_HOME
> > "/usr/local/pi/nodes/data/registration/pimgr/reg/ca/config
> > "
> >     SetEnv PIMGR_PATH "/usr/local/pi/nodes/data/registration/pimgr"
> >     SetEnv DJANGO_SETTINGS_MODULE pimgr.settings
> >     PythonDebug On
> > </Location>
> >
>
-- 
"Little by little, through patience and repeated effort, the mind will
become stilled in the Self." - Bhagawad Gita
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