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Date: Sat, 25 Apr 2009 23:18:43 -0700
Message-ID: <5ddb50770904252318o134b8658xb73831e34304d715@mail.gmail.com>
From: Jonathan Zuckerman <j.zuckerman@gmail.com>
To: users@httpd.apache.org
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Subject: Re: [users@httpd] Dot extremely slow when called from python cgi
	script

On Saturday, April 25, 2009, Dan Yamins <dyamins@gmail.com> wrote:
> I'm having a problem with performance of the program "dot" (for rendering=
 graphs) when called from a python cgi script, served by an apache virtual =
host.=A0 I'm writing this email both the apache httpd list as well as the g=
raphviz users lists (hoping some intersection might be useful).
>

Have you got fastcgi enabled? I doubt seriously that it would account
fir 3.94 seconds but might help a little bit.. I believe it caches
opcode..

Also have you thought about reading the apache log? If the time
differential really is on the apache side I'm sure there will be reams
of data to slog through
> I'm using OSX 10.5.6 and graphviz2.22 (built via macports).
>
> When I run a simple python script that calls dot (via a system call) to r=
ender a small graph, it takes about .04 seconds, which is normal.=A0 But wh=
en I run the same call via CGI script it takes roughly 100 times longer (4 =
seconds).=A0=A0=A0=A0 I've tried graphs of various sizes, ranging from very=
 tiny graphs (4 nodes) to much larger graphs. =A0 The 4 seconds figure for =
the CGI script doesn't change much except for very large graphs, so the tim=
e spent in the CGI script is probably not coming from the actual rendering =
itself.
>
> Not all system calls in my CGI scripts take longer than their "regular ca=
lled at the prompt" version (e.g. if I do a simple 'pwd' it is comparable i=
n time when called in the CGI script versus the non-served script.=A0=A0 (A=
nd many others perform fine.)=A0=A0 The problem just seems to be with the g=
raphviz dot executable.
>
> Below are the two test scripts that when run on my machine illustrate the=
 problem.
>
> Any help (from either community) would be great.
>
> Thanks!
> Dan
>
>
> Here's the python script: run as "python test.py"
>
> ------test.py-----------------
> import os, time
>
> T =3D time.time()
> os.system('/opt/local/bin/dot -Tsvg -o test.svg graph.dot')
> print time.time() - T=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 #output h=
ere is 0.04 seconds
> T =3D time.time()
> os.system('pwd > testout.txt')
> print time.time() - T=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 #output h=
ere is 0.003 seconds
>
>
> Here's the CGI script:=A0 run by navigating to the proper URL for the vir=
tual host on my local machine
>
> ------test.cgi----------------
>
> #!/Library/Frameworks/Python.framework/Versions/Current/bin/python
>
> import time
> import cgi, os
>
> print 'Content-Type: text/html; charset=3Dutf-8\n\n'
> os.chdir('../../Temp')
> T =3D time.time()
> os.system('/opt/local/bin/dot -Tsvg -o test.svg graph.dot')
> print time.time() - T=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 #ou=
tput here is like 4 seconds
> T =3D time.time()
> os.system('pwd > testout.txt')
> print time.time() - T=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 #outpu=
t here is 0.003 seconds
>
>
>
>
>

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