# \--with-debug compile option **URL:** \ **Category:** NGINX\ **Created:** [June 27, 2012, 4:24am UTC](https://www.ruby-forum.com/t/with-debug-compile-option/220980 "2012-06-27T04:24:58Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![aris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/258eb7/32.png) [@aris](https://www.ruby-forum.com/u/aris)\ **Post date:** [June 27, 2012, 4:24am UTC](https://www.ruby-forum.com/t/with-debug-compile-option/220980/1 "2012-06-27T04:24:58Z")
Hi, I need to compile Nginx with --with-debug option. Will there be any performance implications if I have this flag set but NOT set the error log to debug\_\* when I don’t want to debug or troubleshoot any issue? Posted at Nginx Forum: > **[\--with-debug compile option](https://forum.nginx.org/read.php?2,227963,227963#msg-227963)** > > Hi, I need to compile Nginx with --with-debug option. Will there be any performance implications if I have this flag set but NOT set the error log to debug\_\* when I don't want to debug or troubleshoot any issue? ---
**Author:** ![paphillon](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/67e7ee/32.png) [@paphillon](https://www.ruby-forum.com/u/paphillon)\ **Post date:** [June 27, 2012, 5:07am UTC](https://www.ruby-forum.com/t/with-debug-compile-option/220980/2 "2012-06-27T05:07:02Z")
On Tue, Jun 26, 2012 at 10:24:11PM -0400, paphillon wrote: > I need to compile Nginx with --with-debug option. > > Will there be any performance implications if I have this flag set but > NOT set the error log to debug\_\* when I don’t want to debug or > troubleshoot any issue? No. Using [Core functionality](http://nginx.org/r/debug_connection) is also worth considering. ---
**Author:** ![paphillon](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/67e7ee/32.png) [@paphillon](https://www.ruby-forum.com/u/paphillon)\ **Post date:** [June 27, 2012, 9:44am UTC](https://www.ruby-forum.com/t/with-debug-compile-option/220980/3 "2012-06-27T09:44:38Z")
On Wed, Jun 27, 2012 at 02:20:15PM +0800, agentzh wrote: > Even though the current error log level is set higher than “debug”, > there will still be C function call overhead for all those > ngx\_log\_debugN calls. These aren’t functions but are macros that first check if log\_level is set for debugging, and they don’t pessimize performance in any measurable way. > Also, both the nginx core and lots of 3rd-party modules have chunks of > debugging code protected by the “#if (NGX\_DEBUG)” and “#endif” C > macros, which won’t get even compiled when --with-debug is not > specified. The same holds true for ngx\_log\_debugN() macros. > Generally speaking, more code compiled (and run) means more > bugs. I can catch issues in the debugging code from time to time. Most of these allocate some register/stack space, do some assignments, and empty loop at worst. Some of these can be optimized by first checking if log\_level was set for debugging (like is done in ngx\_select\_process\_events(), for example). Still, think they don’t pessimize performance measurable. (There’s some debugging code in SSL that’s not conditional on the log\_level to be set for debugging.) ---
**Author:** ![paphillon](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/67e7ee/32.png) [@paphillon](https://www.ruby-forum.com/u/paphillon)\ **Post date:** [June 27, 2012, 8:21am UTC](https://www.ruby-forum.com/t/with-debug-compile-option/220980/4 "2012-06-27T08:21:01Z")
Hello! On Wed, Jun 27, 2012 at 10:24 AM, paphillon [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I need to compile Nginx with --with-debug option. > > Will there be any performance implications if I have this flag set but > NOT set the error log to debug\_\* when I don’t want to debug or > troubleshoot any issue? Even though the current error log level is set higher than “debug”, there will still be C function call overhead for all those ngx\_log\_debugN calls. Also, both the nginx core and lots of 3rd-party modules have chunks of debugging code protected by the “#if (NGX\_DEBUG)” and “#endif” C macros, which won’t get even compiled when --with-debug is not specified. Generally speaking, more code compiled (and run) means more bugs. I can catch issues in the debugging code from time to time. We usually do not use nginx builds with --with-debug in production environments but we also prepare a separate debugging build at the same time. Best regards, -agentzh