[cfe-commits] r60900 - in /cfe/trunk: include/clang/Parse/Ownership.h
Sebastian Redl
sebastian.redl at getdesigned.at
Sat Dec 13 15:21:59 PST 2008
Sebastian Redl wrote:
> Fariborz Jahanian wrote:
>
>> I am having the same concerns as Steve. We are adding enormous level
>> of abstractions without looking at its consequences down the road.
>> Aren't we
>> concerned about potential performance implications for one (smart
>> pointers don't
>> get smart for cheap :).
>>
> They're not free, but they are pretty cheap. However, Doug messed up my
> planned performance test by doing his name lookup rework at the same
> time as I did the replacements. I still plan to do some serious testing
> soon; however, I expect the largest impact to come from transforming the
> Action interface to smart pointers, and I have only started with this.
>
So I did some rough performance testing. My test method was thus:
time Release/bin/clang -fsyntax-only insn-attrtab.i
where insn-attrtab.i is a preprocessed version of GCC's insn-attrtab.c,
a generated 3.3MB behemoth consisting mostly of a huge switch statement.
I went through the SVN log and tested every version directly before and
after every smart pointer-related commit of mine. I'm happy to say that
over the entire length of the tested area (-r 60760:60983) the average
user time needed to process the file has not changed significantly. A
rough average (read: me running the command 5-10 times and taking a
number that appeared to be in the middle of the observed times) went
from 0.50 for 60760 to 0.52 for 60983, with a variation of +-0.03. I
conclude that the changes done so far had no significant impact on
performance.
I'll keep testing.
Sebastian
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