Anastasia added a comment. In https://reviews.llvm.org/D21698#546733, @yaxunl wrote:
> In https://reviews.llvm.org/D21698#540237, @Anastasia wrote: > > > I have made an experiment with a simple kernel: > > > > void foo1(void); > > void foo2(void); > > void foo3(void); > > void foo4(void); > > void foo5(void); > > void foo6(void); > > void foo7(void); > > void foo8(void); > > void foo9(void); > > void foo10(void); > > > > void test(){ > > foo1(); > > foo2(); > > foo3(); > > foo4(); > > foo5(); > > foo6(); > > foo7(); > > foo8(); > > foo9(); > > foo10(); > > } > > > > > > I am using time utility of linux to measure the compile time running Clang > > in CL2.0 mode and average over 100 samples. It shows me around 7% overhead > > with your approach. > > > Since the program is very small, it is difficult to measure the compilation > time accurately. I compile the program 1000 times and measure its time in a > script: > > $ cat run.sh > run() { > i=1 > while [[ $i -le 1000 ]]; do > ./$1 -cc1 -emit-llvm tmp.cl > i=$((i+1)) > done > } > > time -p run $1 > > > > Even so, I found large variations in the measured compilation time. I ran the > script 10 times for clang before my change and I got the real time > > real 8.96 > real 9.01 > real 8.99 > real 9.07 > real 9.03 > real 8.99 > real 9.03 > real 9.01 > real 8.99 > real 9.01 > > > > and the average time is 9.009s. > > For clang after my change, I got > > real 9.06 > real 9.09 > real 9.10 > real 9.03 > real 9.05 > real 9.17 > real 9.08 > real 9.08 > real 9.07 > real 9.08 > > > > And the average time is 9.081s. > > The increase of compilation time is 0.8%. Considering this program consists > mostly of function declarations, which emphasized the cost of evaluating > disabled function declarations unrealistically. In real programs this > increment in compilation time should be even smaller. > > Since the increment of compilation time is less than 1% even for exaggerated > cases, I think it is reasonable to accept the cost for the improved > diagnostics for extensions. > > If there are concerns that the newly added diagnostics may break applications > which use builtin functions associated with an extension without enabling it, > we can make the diagnostic msg a warning which can be turned off. Ok. Sure. I will profile a few more benchmarks and let you know. https://reviews.llvm.org/D21698 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
