On 2009-Jul-28 01:22:58 +0100, David Kirkby <david.kir...@onetel.net> wrote: >I noticed that several packages build Sage with the -g option to , >which adds debugging information. This has 3 downsides > >1) The binaries are slower
gcc allows '-O -g' so the binaries shouldn't be slower when gcc is used. Some other C/C++ compilers don't allow optimisation with debugging so debug versions would be slower there. >2) The binaries are bigger The filesize on disk is much larger (3-4 times is probably reasonable for C/C++ code but it depends a lot on how much variable typing information needs to be included - ie how heavily typedefs and structs are used). The debug information is not loaded into memory so the RAM footprint is unchanged. >3) Possibly takes longer to compile - I've not verified this, but I >suspect it does. The actual compilation time increases slightly as the compiler needs to generate the debug information. The wallclock time can increase significantly due to all the extra file I/O. Much of sage is not compiled using gcc (python etc) and this won't be impacted by building the C code with debugging so the overall impact will not be as severe. >I think it would be a good idea to remove the -g flag in general. As >far as I am aware, there is the SAGE_DEBUG variable, which should be >set to 1 for debugging. I tend to agree: Keep in mind that the '-g' flag will only help with debugging binary code - debugging the python/lisp/... code is unaffected. -- Peter Jeremy
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