Devel::NYTProf::Apache - Profile mod_perl applications with Devel::NYTProf
# in your Apache config file with mod_perl installed PerlPassEnv NYTPROF PerlModule Devel::NYTProf::Apache
If you're using virtual hosts with
PerlOptions that include either
+Clone then see "VIRTUAL HOSTS" below.
This module allows mod_perl applications to be profiled using
If the NYTPROF environment variable isn't set at the time Devel::NYTProf::Apache is loaded then Devel::NYTProf::Apache will issue a warning and default it to:
The file actually created by NTProf will also have the process id appended to it because the
addpid option is enabled by default.
See "ENVIRONMENT VARIABLES" in Devel::NYTProf for more details on the settings effected by this environment variable.
PerlPassEnv in your httpd.conf if you can set the NYTPROF environment variable externally. Note that if you set the NYTPROF environment variable externally then the file name obviously can't include the parent process id. For example, to set stmts=0 externally, use:
Each profiled mod_perl process will need to have terminated cleanly before you can successfully read the profile data file. The simplest approach is to start the httpd, make some requests (e.g., 100 of the same request), then stop it and process the profile data.
Alternatively you could send a TERM signal to the httpd worker process to terminate that one process. The parent httpd process will start up another one for you ready for more profiling.
It's usually a good idea to use just one child process when profiling, which you can do by setting the
MaxClients to 1 in httpd.conf.
MaxRequestsPerChild to 0 to avoid worker processes exiting and restarting during the profiling, which would split the profile data across multiple files.
IfDefine blocks lets you leave the profile configuration in place and enable it whenever it's needed by adding
-D NYTPROF to the httpd startup command line.
<IfDefine NYTPROF> MaxClients 1 MaxRequestsPerChild 0 PerlModule Devel::NYTProf::Apache </IfDefine>
With that configuration you should get two profile files, one for the parent process and one for the worker.
If your httpd configuration includes virtual hosts with
PerlOptions that include either
+Clone then mod_perl2 will create a new perl interpreter to handle requests for that virtual host. This causes some issues for profiling.
Devel::NYTProf::Apache is loaded in the top-level configuration then activity in any virtual hosts that use their own perl interpreter won't be profiled. Normal virtual hosts will be profiled just fine.
You can profile a single virtual host that uses its own perl interpreter by loading
Devel::NYTProf::Apache inside the configuration for that virtual host. In this case do not use
PerlModule directive. You need to use a
Perl directive instead, like this:
<VirtualHost *:1234> ... <Perl> use Devel::NYTProf::Apache; </Perl> ... </VirtualHost>
Profiling mod_perl on Windows is not supported because NYTProf currently doesn't support threads.
Truncated profile: Profiles for large applications can take a while to write to the disk. Allow sufficient time after stopping apache, or check the process has actually exited, before trying to read the profile.
Truncated profile: The mod_perl child_terminate() function terminates the child without giving perl an opportunity to cleanup. Since
Devel::NYTProf::Apache doesn't intercept the mod_perl child_terminate() function (yet) the profile will be corrupted if it's called. You're most likely to encounter this when using Apache::SizeLimit, so you may want to disable it while profiling.
<akaplan at nytimes.com> Tim Bunce, http://www.tim.bunce.name and http://blog.timbunce.org Steve Peters,
<steve at fisharerojo.org>
Copyright (C) 2008 by Adam Kaplan and The New York Times Company. Copyright (C) 2008 by Steve Peters. Copyright (C) 2008-2012 by Tim Bunce.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.8 or, at your option, any later version of Perl 5 you may have available.