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qemu / qemu / 50290c002c045280f8defad911901e16bfb52884
commit50290c002c045280f8defad911901e16bfb52884[log] [tgz]
authorAlex Bennée <alex.bennee@linaro.org>Wed May 29 17:16:32 2019 +0100
committerAlex Bennée <alex.bennee@linaro.org>Wed Jun 12 17:53:22 2019 +0100
treec432853313b60bfe43c5fe6db27756d847ccd1bf
parent9b109f566adff4d394806b046b395363e523bd80 [diff]
qemu-io-cmds: use clock_gettime for benchmarking

The previous use of gettimeofday() ran into undefined behaviour when
we ended up doing a div 0 for a very short operation. This is because
gettimeofday only works at the microsecond level as well as being
prone to discontinuous jumps in system time. Using clock_gettime with
CLOCK_MONOTONIC gives greater precision and alleviates some of the
potential problems with time jumping around.

We could use CLOCK_MONOTONIC_RAW to avoid being tripped up by NTP and
adjtime but that is Linux specific so I decided it would do for now.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
1 file changed
tree: c432853313b60bfe43c5fe6db27756d847ccd1bf
  1. accel/
  2. audio/
  3. authz/
  4. backends/
  5. block/
  6. bsd-user/
  7. chardev/
  8. contrib/
  9. crypto/
  10. default-configs/
  11. disas/
  12. docs/
  13. fpu/
  14. fsdev/
  15. gdb-xml/
  16. hw/
  17. include/
  18. io/
  19. libdecnumber/
  20. linux-headers/
  21. linux-user/
  22. migration/
  23. nbd/
  24. net/
  25. pc-bios/
  26. po/
  27. python/
  28. qapi/
  29. qga/
  30. qobject/
  31. qom/
  32. replay/
  33. roms/
  34. scripts/
  35. scsi/
  36. stubs/
  37. target/
  38. tcg/
  39. tests/
  40. trace/
  41. ui/
  42. util/
  43. capstone
  44. dtc
  45. slirp
  46. .cirrus.yml
  47. .dir-locals.el
  48. .editorconfig
  49. .exrc
  50. .gdbinit
  51. .gitignore
  52. .gitlab-ci.yml
  53. .gitmodules
  54. .gitpublish
  55. .mailmap
  56. .patchew.yml
  57. .shippable.yml
  58. .travis.yml
  59. arch_init.c
  60. balloon.c
  61. block.c
  62. blockdev-nbd.c
  63. blockdev.c
  64. blockjob.c
  65. bootdevice.c
  66. bt-host.c
  67. bt-vhci.c
  68. Changelog
  69. CODING_STYLE
  70. configure
  71. COPYING
  72. COPYING.LIB
  73. cpus-common.c
  74. cpus.c
  75. device-hotplug.c
  76. device_tree.c
  77. disas.c
  78. dma-helpers.c
  79. dump.c
  80. exec.c
  81. gdbstub.c
  82. gitdm.config
  83. HACKING
  84. hmp-commands-info.hx
  85. hmp-commands.hx
  86. hmp.c
  87. hmp.h
  88. ioport.c
  89. iothread.c
  90. job-qmp.c
  91. job.c
  92. Kconfig.host
  93. LICENSE
  94. MAINTAINERS
  95. Makefile
  96. Makefile.objs
  97. Makefile.target
  98. memory.c
  99. memory_ldst.inc.c
  100. memory_mapping.c
  101. module-common.c
  102. monitor.c
  103. numa.c
  104. os-posix.c
  105. os-win32.c
  106. qdev-monitor.c
  107. qemu-bridge-helper.c
  108. qemu-deprecated.texi
  109. qemu-doc.texi
  110. qemu-edid.c
  111. qemu-ga.texi
  112. qemu-img-cmds.hx
  113. qemu-img.c
  114. qemu-img.texi
  115. qemu-io-cmds.c
  116. qemu-io.c
  117. qemu-keymap.c
  118. qemu-nbd.c
  119. qemu-nbd.texi
  120. qemu-option-trace.texi
  121. qemu-options-wrapper.h
  122. qemu-options.h
  123. qemu-options.hx
  124. qemu-seccomp.c
  125. qemu-tech.texi
  126. qemu.nsi
  127. qemu.sasl
  128. qmp.c
  129. qtest.c
  130. README
  131. replication.c
  132. replication.h
  133. rules.mak
  134. thunk.c
  135. tpm.c
  136. trace-events
  137. VERSION
  138. version.rc
  139. vl.c
  140. win_dump.c
  141. win_dump.h