On 01/08/2013 08:38 AM, Marek Olšák wrote:
This reverts commit 122345876479cf5cf553e38162ab105658614ab7.

Some distributions use --enable-debug for testing packages and the commit
results in terrible CPU performance. It can be embarrassing for us.

Surely people should understand that enabling debugging code/flags can adversely effect performance.


Those who do not want optimizations should set the CFLAGS and CXXFLAGS
environment variables. In my opinion, --enable-debug should only set -DDEBUG.

Previously, if we set --enable-debug we got -g -O2 which was pretty much useless if you planned to use gdb (and why else would you use --enable-debug?). That's why I advocated -g -O0.

Just setting -DDEBUG can lead to reduced performance too (in Mesa or in any other project). For example in the past I've done stuff like:

#ifdef DEBUG
   do extra validation, error checking etc.
#endif

which could significantly impact performance, regardless of -g or -O.

-Brian
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