Multiple Interpreters mod_python optimization

zsi <zsi-iFAglnOhbKNknbxzx/[email protected]>
Newsgroups gmane.comp.python.mod_python
Message-ID <[email protected]> 
Hey *

I am creating a SOAP service that is based on ZSI and mod_python. I have
the service running and it works, but it's not performing well, so I made
did some output to the syslog from inside the handler:

reloadchecker.py:
----------------
testvar=1
----------------

My handler:
----------------
import capa0_9.soap.sessionservice as sessionservice
import capa0_9.soap.zsi_handler as zsi_handler
from mod_python import apache
import capa0_9.tools.log as log
import os,reloadchecker

mod = __import__('encodings.utf_8', globals(), locals(), '*')
mod = __import__('encodings.utf_16_be', globals(), locals(), '*')

def handler(req):

        """
        The PythonHandler entry-point. This function must be present in
order to have mod_apache dispatch a python operation.
        """
        zsi_handler.AsHandler(modules=(sessionservice,), request=req)
        log.debug("REQUESTINFO: Interpreter Name = %s" %
str(req.interpreter))
        log.debug("REQUESTINFO: os.getpid()      = %s" % str(os.getpid()))
        log.debug("REQUESTINFO: reloadchecker    = %s" %
str(reloadchecker.testvar))
        reloadchecker.testvar += 1
        return apache.OK
-----------------

I log the interpreter name, which according to section 4.1 should make
mod_python boost performance by keeping the interpreter alive as long as
the apache server processes. And I log the pid of the interpreter. As it is
clear to see in the output below a new pid is spawned each time, it does
not reuse the interpreter and therefore, I guess, it has to reload
everything for each request. Note that i also list the apache2 processes
before and after I bombard the server with requests, it shows that the same
processes are running before and after. I also made a dummy module
"reloadchecker" that contains one variable "testvar". If it is reloaded the
variable is initialized to 1, if it was already loaded it should be
increased by 1 for each request.

Am I missing something, shouldn't mod_python optimize performance by
reusing previously loaded modules from earlier requests?


mikrov@capa-server:/srv/capa/www/0.9$ sudo ps aux | grep apache2
mikrov    7396  0.0  0.1   3004   764 pts/2    S+   11:11   0:00 grep
apache2
root     22343  0.0  1.0  13728  5336 ?        Ss   May14   0:26
/usr/sbin/apache2 -k start
root     22346  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22347  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22348  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22349  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22350  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22383  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22392  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22407  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22716  0.0  0.6  13728  3136 ?        S    May14   0:03
/usr/sbin/apache2 -k start
root     23356  0.0  0.6  13728  3136 ?        S    May14   0:03
/usr/sbin/apache2 -k start

mikrov@capa-server:/srv/capa/www/0.9/sessionservice$ sudo tail -f
/var/log/syslog | grep REQUESTINFO
May 15 11:52:03 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/ 
May 15 11:52:03 capa-server capa: REQUESTINFO: os.getpid()      = 7953     
                        
May 15 11:52:03 capa-server capa: REQUESTINFO: reloadchecker    = 1        
                        
May 15 11:52:03 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/ 
May 15 11:52:03 capa-server capa: REQUESTINFO: os.getpid()      = 7954     
                        
May 15 11:52:03 capa-server capa: REQUESTINFO: reloadchecker    = 1        
                        
May 15 11:52:04 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/ 
May 15 11:52:04 capa-server capa: REQUESTINFO: os.getpid()      = 7955     
                        
May 15 11:52:04 capa-server capa: REQUESTINFO: reloadchecker    = 1        
                        
May 15 11:52:05 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/ 
May 15 11:52:05 capa-server capa: REQUESTINFO: os.getpid()      = 7959     
                        
May 15 11:52:05 capa-server capa: REQUESTINFO: reloadchecker    = 1        
                        
May 15 11:52:06 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/ 
May 15 11:52:06 capa-server capa: REQUESTINFO: os.getpid()      = 7960     
                        
May 15 11:52:06 capa-server capa: REQUESTINFO: reloadchecker    = 1        
                        
May 15 11:52:07 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/ 
May 15 11:52:07 capa-server capa: REQUESTINFO: os.getpid()      = 7961     
                        
May 15 11:52:07 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:08 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:08 capa-server capa: REQUESTINFO: os.getpid()      = 7963
May 15 11:52:08 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:08 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:08 capa-server capa: REQUESTINFO: os.getpid()      = 7964
May 15 11:52:08 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:09 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:09 capa-server capa: REQUESTINFO: os.getpid()      = 7966
May 15 11:52:09 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:10 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:10 capa-server capa: REQUESTINFO: os.getpid()      = 7968
May 15 11:52:10 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:11 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:11 capa-server capa: REQUESTINFO: os.getpid()      = 7969
May 15 11:52:11 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:12 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:12 capa-server capa: REQUESTINFO: os.getpid()      = 7970
May 15 11:52:12 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:13 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:13 capa-server capa: REQUESTINFO: os.getpid()      = 7972
May 15 11:52:13 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:13 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:13 capa-server capa: REQUESTINFO: os.getpid()      = 7973
May 15 11:52:13 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:14 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:14 capa-server capa: REQUESTINFO: os.getpid()      = 7974
May 15 11:52:14 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:15 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:15 capa-server capa: REQUESTINFO: os.getpid()      = 7976
May 15 11:52:15 capa-server capa: REQUESTINFO: reloadchecker    = 1
May 15 11:52:16 capa-server capa: REQUESTINFO: Interpreter Name =
/srv/capa/www/0.9/sessionservice/
May 15 11:52:16 capa-server capa: REQUESTINFO: os.getpid()      = 7977
May 15 11:52:16 capa-server capa: REQUESTINFO: reloadchecker    = 1

mikrov@capa-server:/srv/capa/www/0.9$ sudo ps aux | grep apache2
mikrov    7457  0.0  0.1   3004   764 pts/2    S+   11:12   0:00 grep
apache2
root     22343  0.0  1.0  13728  5336 ?        Ss   May14   0:26
/usr/sbin/apache2 -k start
root     22346  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22347  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22348  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22349  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22350  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22383  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22392  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22407  0.0  0.6  13728  3136 ?        S    May14   0:04
/usr/sbin/apache2 -k start
root     22716  0.0  0.6  13728  3136 ?        S    May14   0:03
/usr/sbin/apache2 -k start
root     23356  0.0  0.6  13728  3136 ?        S    May14   0:03
/usr/sbin/apache2 -k start

Best regards
Jakob Simon-Gaarde
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