force IRAM_ATTR ? / default to IRAM_ATTR

[djamu-]

I was wondering if there's an option to default to IRAM_ATTR, to make everything load into IRAM. ( or a global linker option ?)
The reason why I'm asking and forgive me my ignorance, is that by far the majority of projects will fit into ram, and will quite a bit faster for those that don't fit into the cache.
Cache misses are a problem when a tight timing is necessary. I mean much faster then the 1kHz RTOS tick.

It took me a few days to figure out the issue with cache misses the first time I wrote running code that exceeded the cache size, resulting in jittery behavior, which I regularly fix by adding IRAM_ATTR to any function except setup code.

Currently I'm porting a large project to esp32 and adding IRAM_ATTR everywhere is quite tedious.

My question is probably a feature request, I propose making IRAM_ATTR the default and to add either a NOIRAM_ATTR / FLASH_ATTR attribute.

By far the majority of projects will fit into IRAM, and for those that don't, the new attribute will run code that doesn't need to be called often or once, like setup code or static webpages for example onto flash.
As a matter of fact I find it quite strange that it's not the default behavior, it's like writing an app for PC and telling it > don't use ram for code, run it from HD, which everybody knows is a terrible idea.

[ESP_Sprite]

By far the majority of projects will fit into IRAM

That is a very strange assertion. A very simple example (esp-idf/examples/wifi/getting_started/station/) when you run 'esp.py size' 'idf.py size' on it will give you the following:

Code: Select all

 DRAM .data size:   16632 bytes
 DRAM .bss  size:   15504 bytes
Used static DRAM:   32136 bytes ( 148600 available, 17.8% used)
Used static IRAM:   88469 bytes (  42603 available, 67.5% used)
      Flash code:  474391 bytes
    Flash rodata:   92368 bytes
Total image size:~ 671860 bytes (.bin may be padded larger)

Disregarding everything else, the code in this (very simple) example already is (88469+474391=)549KiB. That's more memory than the ESP32 has *in total*, and that's ignoring the fact that only a fraction of that is (usable as) IRAM.

[axellin]

By far the majority of projects will fit into IRAM

That is a very strange assertion. A very simple example (esp-idf/examples/wifi/getting_started/station/) when you run 'esp.py size' on it will give you the following:

I think you mean 'idf.py size'.

[ESP_Sprite]

I think you mean 'idf.py size'.

You are correct, thanks, I changed it.