[jira] [Updated] (IGNITE-16879) Estimate time-to-write-cp-page and time-to-fsync-cp-page empirically

["Ivan Bessonov (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IGNITE-16879?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ivan Bessonov updated IGNITE-16879:
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    Attachment: Screenshot from 2025-04-15 12-45-07.png

> Estimate time-to-write-cp-page and time-to-fsync-cp-page empirically
> --------------------------------------------------------------------
>
>                 Key: IGNITE-16879
>                 URL: https://issues.apache.org/jira/browse/IGNITE-16879
>             Project: Ignite
>          Issue Type: Improvement
>          Components: persistence
>            Reporter: Roman Puchkovskiy
>            Assignee: Ivan Bessonov
>            Priority: Major
>         Attachments: Screenshot from 2025-04-15 12-45-07.png
>
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> The speed-based throttling (implemented in  SpeedBasedMemoryConsumptionThrottlingStrategy) tries to estimate how much time is needed to fully write a checkpoint to disk. To write a page to disk, we not only need to pass it to the OS for writing (which takes time), but also fsync it to disk (which also takes some time).
> When estimating the time needed to write a checkpoint, the speed-based throttle needs an estimation of how much time it is needed to write a page and how much time is needed to fsync it. Currently, a naive approximation is used: page writing time is equal to page fsyncing time.
> In reality, this is not true, so the speed estimations are off: the more the ratio between writing and syncing time differs from 1, the worse our estimation is.
> The idea is to actually measure the average time to write a page and fsync a page to disk and then use these measured values to obtain better estimations.



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