Little FS IO operation gets extremely slow

RE: Little FS IO operation gets extremely slow

AHaug — Fri, 01 Dec 2023 08:08:08 GMT

Thank you for elaborating

What I believe is happening is that you've reached the garbage collection part of the littlefs design.

This case, When ist littlefs garbage collection / flash erase block called? mentions this briefly and links to the design-readme of littlefs: https://github.com/littlefs-project/littlefs/blob/master/DESIGN.md which should elaborate on it

The garbage collection procedure takes quite a while, so I would recommend you to investigate if this is what you're observing

Kind regards,
Andreas

RE: Little FS IO operation gets extremely slow

imtiz_ahmed — Thu, 30 Nov 2023 02:56:52 GMT

Hello,

[quote userid="107683" url="~/f/nordic-q-a/106074/little-fs-io-operation-gets-extremely-slow/457897"]This is a bit unclear to us, could you elaborate what you mean when you do this? [/quote]

I am using nRF52840 dev kit and used one of the sample projects called LittleFS. I am not doing anything other than writing 1KB array in new file. I call the function that does the file IO in a loop, the function opens a new file in create mode, writes the 1KB array to it and then closes it. The code is as basic as it can get.

[quote userid="107683" url="~/f/nordic-q-a/106074/little-fs-io-operation-gets-extremely-slow/457897"]The amount of time this takes could also indicate that either something not beeing properly connected or that the application does something important for a long time before it allows for FS to do its thing. Could you check and verify if this is not the case?[/quote]

Again, since I am using nRF52840 dev kit and the external flash (mx25r64) that comes mounted on the dev board, I am not sure there is any chance of improper connection. It is not a custom board.

BTW, I have attached the full sample project that can be run on nRF52840 dev kit to see the results, if you happen to have the time for it of course.

Thanks for taking time to reply!

RE: Little FS IO operation gets extremely slow

AHaug — Tue, 28 Nov 2023 14:21:20 GMT

Hi,

Could you state which pins you're using that results in this speed?

[quote user="imtiz_ahmed"]One strange thing I have notice is that if you add fs_unlink(fname); after fs_close(&file); inside fs_write_bytes_to_file(...), which of course will delete the file after it is written, everything works fine, I tried with the loop of 1000 and I could get 9 files per sec, by if I do not delete the file, I get avg or 2 or 3 files a sec. [/quote]

This is a bit unclear to us, could you elaborate what you mean when you do this?

[quote user=""]But sometimes one of the step (out of opening, writing or closing file) gets stuck for upto 13 seconds. [/quote]

The amount of time this takes could also indicate that either something not beeing properly connected or that the application does something important for a long time before it allows for FS to do its thing. Could you check and verify if this is not the case?

Kind regards,
Andreas

RE: Little FS IO operation gets extremely slow

imtiz_ahmed — Tue, 28 Nov 2023 07:15:12 GMT

Hi,

Please do let me know if you find something.

Thanks!

RE: Little FS IO operation gets extremely slow

AHaug — Fri, 24 Nov 2023 15:09:55 GMT

Hi,

I've unfortunately been out of office due to illness this week. I will check back with you and this case early next week

Apologies for the inconvinience

Kind regards,
Andreas

RE: Little FS IO operation gets extremely slow

imtiz_ahmed — Fri, 24 Nov 2023 04:32:39 GMT

Andreas

Any feedback?

RE: Little FS IO operation gets extremely slow

imtiz_ahmed — Tue, 21 Nov 2023 16:18:44 GMT

One strange thing I have notice is that if you add fs_unlink(fname); after fs_close(&file); inside fs_write_bytes_to_file(...), which of course will delete the file after it is written, everything works fine, I tried with the loop of 1000 and I could get 9 files per sec, by if I do not delete the file, I get avg or 2 or 3 files a sec.

RE: Little FS IO operation gets extremely slow

imtiz_ahmed — Tue, 21 Nov 2023 16:15:01 GMT

devzone.nordicsemi.com/.../2620.littlefs.zip

There you go, it is very basic code, just calling a test method in the loop in main and in that test method, i give values to 1024 bytes array and then call another method "fs_write_bytes_to_file" to create file with that data. Nothing special.

RE: Little FS IO operation gets extremely slow

imtiz_ahmed — Tue, 21 Nov 2023 16:11:22 GMT

Sure, I will give you zip of project in a short while. It is not even my firmware, just the sample project called LittleFS with some minor changes to write files in a loop. The output looks something like this, where some files just randomly take LOT more time than most of others.

RE: Little FS IO operation gets extremely slow

AHaug — Tue, 21 Nov 2023 15:15:16 GMT

Hi,

I will look into this

Does your firmware do anything other than write to the littlefs partition? Could you upload a minimal version of your project so I can attempt to recreate the behaviour?

Kind regards,
Andreas