Flash Data Storage Garbage Collection takes a long time

[m.li]

Hello,

We are allocating a large amount of pages (100 pages, ~400kB) for the Flash Data Storage module in order to hold collected data. As a result, the fds garbage collection will take around 3-10 seconds (depending on how many invalid records are present). This makes sense as during garbage collection, valid records are collected. The pages left will be erased, which will incur the flash page erase time.

However, it appears that the garbage collection will stop interrupts from happening. We will run garbage collection before we save data to flash, which occurs at an interval. As such, our unit will be locked up for a few seconds. We are concerned about this effect on other interrupts (namely RF, timekeeping, and alarms).

Is there a way to run garbage collection in stages? Or a setting so that garbage collection does not block interrupts?

Thank you for your help.

[Simonr]

Hi

You can read about the garbage collection process here. Garbage collection is not run automatically by FDS, but must be started by the application itself. Ideally, you should run garbage collection only when necessary, and when BLE activity is low, otherwise the operation might time out. When garbage collection times out, the FDS_ERR_TIMEOUT is returned by the FDS_EVT_GC event, the system can continue normal operation.

Best regards,

Simon

[m.li]

We have decided to check the FDS status using fds_stat on interval, to see if it necessitates us to perform a garbage collection. We will protect against undefined behaviour from interrupts occuring during the garbage collection.