82xx performance

[Rune Torgersen]

Arnd Bergmann wrote:
> If you can't get it to work, readprofile(1) is a much simpler
> tool, both in what it can do and what it requires you to do.

One thing that pops out is that handle_mm_fault uses twice as many ticks
in arch/powerpc.

Top 20 calls from readprofile
2.6.25 arch/ppc
305993 total                                      0.1295
 53301 __flush_dcache_icache                    832.8281
 25746 clear_pages                              919.5000
 19086 __copy_tofrom_user                        33.3671
 17198 get_page_from_freelist                    13.3525
 12741 _tlbia                                   353.9167
 12317 handle_mm_fault                            8.9774
  9669 handle_page_fault                         75.5391
  8037 do_page_fault                              9.5225
  6450 cpu_idle                                  25.1953
  5430 update_mmu_cache                          21.8952
  4663 copy_page                                 32.3819
  3712 __link_path_walk                           0.8452
  3302 find_vma                                  19.6548
  3241 __do_fault                                 2.6741
  3235 unmap_vmas                                 2.1741
  3184 lru_cache_add_active                      16.5833
  3076 __alloc_pages                              3.8450
  3062 find_lock_page                             9.8141
  2826 zone_watermark_ok                         16.0568
  2593 put_page                                   6.8237


2.6.25 arch/powerpc
 60982 cpu_idle                                 262.8534
 54601 __flush_dcache_icache_phys               650.0119
 25676 clear_pages                              917.0000
 24892 handle_mm_fault                            8.7772
 19478 __copy_tofrom_user                        34.0524
 18112 get_page_from_freelist                    12.3716
 13245 _tlbia                                   367.9167
 11976 do_page_fault                             10.3241
 10028 handle_page_fault                         78.3438
  6025 update_mmu_cache                          23.5352
  4650 page_address                              15.7095
  4097 copy_page                                 28.4514
  4031 __do_fault                                 1.9838
  3952 find_vma                                  27.4444
  3861 __link_path_walk                           0.9237
  3533 unmap_vmas                                 2.2590
  3400 lru_cache_add_active                      19.3182
  3317 find_lock_page                            11.0567
  3238 __alloc_pages                              4.5223
  2825 zone_watermark_ok                         16.8155
  2740 __d_lookup                                 5.8547