[PATCH] D36351: [lld][ELF] Add profile guided section layout

[Rafael Avila de Espindola via llvm-commits]

Rafael Avila de Espindola <rafael.espindola at gmail.com> writes:

I tested the patch by linking chromium.

With the last version of the patch I can measure a small improvement in
L1-icache-load-misses. Somehow iTLB-load-misses seems to get worse:

 Performance counter stats for './default-ld.lld @response.txt -o t --no-threads' (20 runs):

           279,008      iTLB-load-misses                                              ( +-  0.36% )
        17,916,925      L1-icache-load-misses                                         ( +-  0.19% )

       1.165371143 seconds time elapsed                                          ( +-  0.12% )


 Performance counter stats for './sorted-ld.lld @response.txt -o t --no-threads' (20 runs):

           289,396      iTLB-load-misses                                              ( +-  0.77% )
        16,922,395      L1-icache-load-misses                                         ( +-  0.18% )

       1.166535009 seconds time elapsed                                          ( +-  0.12% )

Do you have a suggestion of an open source program that might benefit
more from this optimization?

Cheers,
Rafael