Allwinner A64 arch timer monotonicity test

a64_arch_timer.log

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# test output mainline kernel
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$ ./test_timer 
TAP version 13
# number of cores: 4
ok 1 same timer frequency on all cores
# timer frequency is 24000000 Hz (24 MHz)
# time1: eb447fff, time2: eb444000, diff: -16383
# time1: eb44efff, time2: eb44e800, diff: -2047
# time1: eb4bd7ff, time2: eb4bd000, diff: -2047
# time1: eb4c97ff, time2: eb4c9000, diff: -2047
# time1: eb507fff, time2: eb504000, diff: -16383
# time1: eb54ffff, time2: eb54c000, diff: -16383
# time1: eb58ffff, time2: eb58f800, diff: -2047
# time1: eb627fff, time2: eb624000, diff: -16383
# time1: eb66ffff, time2: eb66c000, diff: -16383
# time1: eb688fff, time2: eb688800, diff: -2047
# time1: eb69ffff, time2: eb69c000, diff: -16383
# time1: eb6b2fff, time2: eb6b2800, diff: -2047
# time1: eb6cffff, time2: eb6cc000, diff: -16383
# time1: eb717fff, time2: eb714000, diff: -16383
# time1: eb79f7ff, time2: eb79f000, diff: -2047
# time1: eb7abfff, time2: eb7ab800, diff: -2047
# too many errors, stopping reports
not ok 2 native counter reads are monotonic # 46 errors
# min: -16383, avg: 0, max: 16384
# diffs: -85209, -682542, -85208, -85208, -682542, -85208, -85208, -85208, -682542, -85208, -85208, -85208, -85208, -85208, -85208, -85208
# too many errors, stopping reports
not ok 3 Linux counter reads are monotonic # 42 errors
# min: -734438724866, avg: 104, max: 734438725074
# core 0: counter value: 4011675693 => 167 sec
# core 0: offsets: back-to-back: 0, b-t-b synced: 1, b-t-b w/ delay: 3
# core 1: counter value: 4011677206 => 167 sec
# core 1: offsets: back-to-back: 1, b-t-b synced: 1, b-t-b w/ delay: 3
# core 2: counter value: 4011678615 => 167 sec
# core 2: offsets: back-to-back: 0, b-t-b synced: 1, b-t-b w/ delay: 3
# core 3: counter value: 4011680036 => 167 sec
# core 3: offsets: back-to-back: 0, b-t-b synced: 1, b-t-b w/ delay: 3
1..3

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# test output with fixed kernel/DT
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$ ./test_timer 
TAP version 13
# number of cores: 4
ok 1 same timer frequency on all cores
# timer frequency is 24000000 Hz (24 MHz)
ok 2 native counter reads are monotonic # 0 errors
# min: 9, avg: 9, max: 1249
ok 3 Linux counter reads are monotonic # 0 errors
# min: 625, avg: 682, max: 38042
# core 0: counter value: 40617494010 => 1692 sec
# core 0: offsets: back-to-back: 12, b-t-b synced: 10, b-t-b w/ delay: 12
# core 1: counter value: 40617495862 => 1692 sec
# core 1: offsets: back-to-back: 12, b-t-b synced: 11, b-t-b w/ delay: 13
# core 2: counter value: 40617497615 => 1692 sec
# core 2: offsets: back-to-back: 11, b-t-b synced: 10, b-t-b w/ delay: 13
# core 3: counter value: 40617499269 => 1692 sec
# core 3: offsets: back-to-back: 16, b-t-b synced: 10, b-t-b w/ delay: 13
1..3