dpdk: replace TSC clock with GetTime (gettimeofday) function v2 #11409
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Getting clock through Time Stamp Counter (TSC) can be precise and fast, however only for a short duration of time. The implementation across CPUs seems to vary. The original idea is to increment the counter with every tick. Then dividing the delta of CPU ticks by the CPU frequency can return the time that passed. However, the CPU clock/frequency can change over time, resulting in uneven incrementation of TSC. On some CPUs this is handled by extra logic. As a result, obtaining time through this method might drift from the real time. This commit therefore substitues TSC time retrieval by the standard system call wrapped in GetTime function - on Linux it is gettimeofday. Ticket: 7115
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## master #11409 +/- ##
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- Coverage 82.45% 82.43% -0.03%
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Files 938 938
Lines 248036 248018 -18
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- Hits 204523 204453 -70
- Misses 43513 43565 +52
Flags with carried forward coverage won't be shown. Click here to find out more. |
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Information: QA ran without warnings. Pipeline 21355 |
victorjulien
approved these changes
Jul 4, 2024
Merged
|
Merged in #11431, thanks! |
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Rebase of #11389
Getting time through the Time Stamp Counter (TSC) can be precise and fast, however only for a short duration of time.
The implementation across CPUs seems to vary. The original idea is to increment the counter with every tick. Then dividing the delta of CPU ticks by the CPU frequency can return the time that passed. However, the CPU clock/frequency can change over time, resulting in uneven incrementation of TSC. On some CPUs, this is handled by extra logic. As a result, obtaining time through this method might drift from real-time.
This commit therefore substitutes TSC time retrieval by the standard system call wrapped in the GetTime function - on Linux it is gettimeofday.
Ticket: 7115
https://redmine.openinfosecfoundation.org/issues/7115
Describe changes:
v2
v1