update memory calculation to match the bosh-agent #57
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ctlong
suggested changes
Nov 1, 2022
- Context from bosh engineers:
Updating System Metrics Agent to use the same memory usage metric that the Bosh Agent uses, that is using MemAvailable over MemUsed. MemAvailable is a more reliable and correct metric than the older hand-calculation that folks do. It is a metric that's maintained by the kernel developers that is intended to tell users how much memory their application can use without causing the system to hit performance issues. This metric was [added back in 2014](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=34e431b0a) by the kernel developers because the old way of calculating available memory was no longer correct due to changes in how Linux uses and frees memory. Furthermore, the kernel devs expected that more changes to kernel memory management would inevitably come, rendering incorrect any calculations based on what the kernel did in 2014. MemAvailable is a solid estimate of the maximum amount of memory that an application can use without causing performance problems, and is a metric that is updated to remain correct as the internal details of how the kernel manage memory change over time.
Signed-off-by: Ben Fuller <[email protected]>
Signed-off-by: Rebecca Roberts <[email protected]>
Signed-off-by: Ben Fuller <[email protected]>
Benjamintf1
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Benjamintf1
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Nov 1, 2022
ctlong
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Nov 1, 2022
This was referenced Jan 27, 2023
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Type of change
Testing performed?
Checklist:
mainbranch, or relevant version branchIf you have any questions, or want to get attention for a PR or issue please reach out on the #logging-and-metrics channel in the cloudfoundry slack
Signed-off-by: Ben Fuller [email protected]