Speculative: Rust for base system components

Brian Neal brian at aceshardware.com
Sun Jan 6 22:06:18 UTC 2019


I'm glad you mentioned build times, because I did, in fact, measure them...

 > Compiler              Flags                 Inst. Count     Build Time
 > ======================================================================
 > clang 7.0.0           none                            33         296ms
 >                        -O3                            23         341ms
 > rustc 1.31.0          none                           110         606ms
 >                        -C opt-level=3                 67         643ms
 > gcc 8.2               none                            37         211ms
 >                        -O2                            24         249ms
 >                        -O3                          119*         206ms


On 1/6/2019 10:01 AM, Alan Somers wrote:
> But it's not a like-for-like comparison.  Rust eliminates dead code at
> a later stage.  If you want to compare the efficiency of generated
> code, you need to exclude the dead code that will be eliminated by
> LTO.  And you shouldn't be counting the labels for either language,
> because they don't affect the machine code.  If you want to compare
> build times, then you should actually measure build times.
> -Alan


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