Out of static IRAM

[espdude]

Dear All,

I believe many of us tried to get as much as possible from ESP32, so I hope at least someone ran into this problem already.
In my project I use BLE (as a peripheral only) and WiFi simultaneuosly. WiFi connection in turn is used to communicate with AWS IoT services and libsodium is used internally for some data encryption. In order to get enough RAM I've decided to go with ESP32-WROVER module with on board SPI RAM and external 16Mb flash for OTA updates. Everything worked fine so far until I tried to add a simple gpio interrupt handler marked with IRAM_ATTR, and after compiling the code I've got the following error:

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/home/user/esp/xtensa-esp32-elf/bin/../lib/gcc/xtensa-esp32-elf/5.2.0/../../../../xtensa-esp32-elf/bin/ld: /home/user/projects/test-fw/build/test_fw.elf section `.iram0.text' will not fit in region `iram0_0_seg'
/home/user/esp/xtensa-esp32-elf/bin/../lib/gcc/xtensa-esp32-elf/5.2.0/../../../../xtensa-esp32-elf/bin/ld: region `iram0_0_seg' overflowed by 47 bytes

I don't have any code in my project with IRAM_ATTR, so obviously it's ESP IDF components filled all IRAM available. I have tried running my interrupt code without IRAM_ATTR, it works, but is far as I understand it is not advisable to do so with time-critical stuff like GPIO interrupt handlers.

My question is there any way to decrease the static IRAM usage by ESP IDF components (either via menuconfig or any other technique) leaving at least some IRAM for my own performance critical code? The obvious solution of removing some libraries and functionality from the project is not an option unfortunately.

Please see the output of "make size components" below:

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$ make size-components
Total sizes:
 DRAM .data size:   15728 bytes
 DRAM .bss  size:   33112 bytes
Used static DRAM:   48840 bytes (  66360 available, 42.4% used)
Used static IRAM:  130951 bytes (    121 available, 99.9% used)
      Flash code:  799362 bytes
    Flash rodata:  145076 bytes
Total image size:~1091117 bytes (.bin may be padded larger)
Per-archive contributions to ELF file:
            Archive File DRAM .data & .bss   IRAM Flash code & rodata   Total
                 libbt.a        473   2428   1492     142739    10746  157878
            libmbedtls.a         92    272     48     117261    19453  137126
           libnet80211.a        314   9221   3565     109308    13178  135586
               liblwip.a         19   3876  10538      88513    15254  118200
 libc-psram-workaround.a        751     28   9628      63164     3887   77458
              libesp32.a       3070    601  18782      25799    25201   73453
                 libpp.a       1229   5274  13275      45250     4208   69236
           libbtdm_app.a        367   4695  19502      36070     3135   63769
                libphy.a       1282    910   5666      29657        0   37515
           libfreertos.a       4152    776  20938          0     2489   28355
             libdriver.a         83     41   2871      12893    10709   26597
             libspiffs.a          0     12      0      24236     1607   25855
                libwpa.a          0    682      0      20941     2312   23935
               libmain.a        451   2592      0       9784    10552   23379
          libnvs_flash.a          0     32      0      13692     3192   16916
     libwpa_supplicant.a          0      0      0      13553     2318   15871
          libspi_flash.a         36    323   7044       1577     1723   10703
            libaws_iot.a          0     25      0       9022     1622   10669
                libsoc.a        657      8   4814        731     4085   10295
               libheap.a        864      8   3585       1229      904    6590
                libgcc.a          4     20    104       5568      888    6584
                libvfs.a        232    103      0       5625      401    6361
            libcoexist.a       1365    106   3708          0        0    5179
 libbootloader_support.a          0      4      0       2525     1474    4003
             libstdc++.a          8     20      0       2689     1253    3970
      libtcpip_adapter.a          0    124      0       2977      377    3478
         libapp_update.a          0     80      0       2132      785    2997
                librtc.a          0      4   2308          0        0    2312
             libnewlib.a        152    272    830        871       84    2209
             libi2cdev.a          0     56      0       1187      512    1755
            libpthread.a         16     12    178        874      632    1712
                liblog.a          8    268    478        740      162    1656
               libcore.a          0      5      0        799      417    1221
    libsmartconfig_ack.a          0      1      0        778      312    1091
             libds3231.a          0      0      0        822        0     822
                libhal.a          0      0    515          0       32     547
        libfactory_nvs.a          0     16      0        311      158     485
               libmesh.a          1      1      0         55        0      57
                libcxx.a          0      0      0         11        0      11
               libwpa2.a          0      1      0          0        0       1
                libwps.a          0      1      0          0        0       1
           libethernet.a          0      0      0          0        0       0

[ESP_igrr]

Can you please check if https://docs.espressif.com/projects/esp ... TIMIZATION option got enabled in sdkconfig somehow? If yes, disabling it should give about 10kB of IRAM.

[espdude]

Hi igrr,

Thank you very much for this advise, indeed the option was enabled in menuconfig and disabling it gave me around 10k of IRAM which should be enough for my ISR handlers.

After disabling the option I've got the following:

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$ make size-components
Total sizes:
 DRAM .data size:   15728 bytes
 DRAM .bss  size:   33104 bytes
Used static DRAM:   48832 bytes (  66368 available, 42.4% used)
Used static IRAM:  120391 bytes (  10681 available, 91.9% used)
      Flash code:  809026 bytes
    Flash rodata:  145076 bytes

Thanks again for you help , this really solves the issue for now, would be great though if Espressif team can plan some further optimizations of IRAM usage by IDF components, even with some performance penalties, because 91.9% is still a high figure and I can imagine a situation when this may be not enough for user application.

[Ritesh]

Hi igrr,

Thank you very much for this advise, indeed the option was enabled in menuconfig and disabling it gave me around 10k of IRAM which should be enough for my ISR handlers.

After disabling the option I've got the following:

Code: Select all

$ make size-components
Total sizes:
 DRAM .data size:   15728 bytes
 DRAM .bss  size:   33104 bytes
Used static DRAM:   48832 bytes (  66368 available, 42.4% used)
Used static IRAM:  120391 bytes (  10681 available, 91.9% used)
      Flash code:  809026 bytes
    Flash rodata:  145076 bytes

Thanks again for you help , this really solves the issue for now, would be great though if Espressif team can plan some further optimizations of IRAM usage by IDF components, even with some performance penalties, because 91.9% is still a high figure and I can imagine a situation when this may be not enough for user application.

Hello,

Which option you have disabled and 10% of IRAM is available for usage? because we are also running same issues at our end after enabling Wi-Fi and Bluetooth together because bluetooth library itself is taking 80 to 90 Kbytes of IRAM.

We are running ESP32 IDF 3.2 version.

Please suggest from your end so that we can able to move further as we are stuck over here.