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gerrit-public.fairphone.software / fp2-dev / platform / external / fio / 71339117638469372f703332d8b969382b12c49b
commit71339117638469372f703332d8b969382b12c49b[log] [tgz]
authorJens Axboe <axboe@kernel.dk>Fri Dec 21 22:54:56 2012 +0100
committerJens Axboe <axboe@kernel.dk>Fri Dec 21 22:54:56 2012 +0100
treeab8c0a5e51204dfb704f47f9b7c3d2f152029409
parent4e59017dd2a031f2b7fbe2931d3c602735b6cfd6 [diff]
clock: turn expensive division into multiply + cheap division

On x86-64, dividing by a variable turns into a hugely expensive
divq. It's much cheaper to invert the division. Instead of
dividing clocks by clocks-per-usec, multiply by a 16M/clocks-per-usec
constant instead.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 file changed
tree: ab8c0a5e51204dfb704f47f9b7c3d2f152029409
  1. arch/
  2. compiler/
  3. crc/
  4. engines/
  5. examples/
  6. lib/
  7. os/
  8. profiles/
  9. t/
  10. .gitignore
  11. backend.c
  12. blktrace.c
  13. blktrace_api.h
  14. cgroup.c
  15. cgroup.h
  16. client.c
  17. COPYING
  18. debug.c
  19. debug.h
  20. diskutil.c
  21. diskutil.h
  22. eta.c
  23. fifo.c
  24. fifo.h
  25. file.h
  26. filehash.c
  27. filehash.h
  28. filesetup.c
  29. FIO-VERSION-GEN
  30. fio.1
  31. fio.c
  32. fio.h
  33. fio_generate_plots
  34. fio_generate_plots.1
  35. flist.h
  36. flow.c
  37. flow.h
  38. gettime-thread.c
  39. gettime.c
  40. gettime.h
  41. hash.h
  42. helpers.c
  43. helpers.h
  44. HOWTO
  45. init.c
  46. io_ddir.h
  47. io_u.c
  48. ioengine.h
  49. ioengines.c
  50. iolog.c
  51. iolog.h
  52. json.c
  53. json.h
  54. libfio.c
  55. LICENSE
  56. log.c
  57. log.h
  58. Makefile
  59. memalign.c
  60. memalign.h
  61. memory.c
  62. minmax.h
  63. mutex.c
  64. mutex.h
  65. options.c
  66. options.h
  67. parse.c
  68. parse.h
  69. profile.c
  70. profile.h
  71. rbtree.c
  72. rbtree.h
  73. README
  74. REPORTING-BUGS
  75. SERVER-TODO
  76. server.c
  77. server.h
  78. smalloc.c
  79. smalloc.h
  80. stat.c
  81. stat.h
  82. time.c
  83. time.h
  84. trim.c
  85. trim.h
  86. verify.c
  87. verify.h