我使用duinotech XC-3800在ESP32芯片上使用ESP IDF测试了运行裸露的代码，并在图像尺寸方面获得了以下结果。
# The following lines of boilerplate have to be in your project's
# CMakeLists in this exact order for cmake to work correctly
cmake_minimum_required(VERSION 3.5)
include($ENV{IDF_PATH}/tools/cmake/project.cmake)
project(temp)
idf_component_register(SRCS "main.c"
INCLUDE_DIRS "")
#include <stdio.h>
void app_main(void) {
printf("Hello world!\n");
for (int i = 10; i >= 0; i--) {
printf("Restarting in %d seconds...\n", i);
}
printf("Restarting now.\n");
fflush(stdout);
}
#include <stdio.h>
void app_main(void) { printf("Hello world!\n"); }
void app_main(void) {}
通过运行idf_size.py build/temp.map
Total sizes:
DRAM .data size: 8320 bytes
DRAM .bss size: 4072 bytes
Used static DRAM: 12392 bytes ( 168344 available, 6.9% used)
Used static IRAM: 38804 bytes ( 92268 available, 29.6% used)
Flash code: 75408 bytes
Flash rodata: 23844 bytes
Total image size:~ 146376 bytes (.bin may be padded larger)
Total sizes:
DRAM .data size: 8320 bytes
DRAM .bss size: 4072 bytes
Used static DRAM: 12392 bytes ( 168344 available, 6.9% used)
Used static IRAM: 38804 bytes ( 92268 available, 29.6% used)
Flash code: 75240 bytes
Flash rodata: 23796 bytes
Total image size:~ 146160 bytes (.bin may be padded larger)
Total sizes:
DRAM .data size: 8320 bytes
DRAM .bss size: 4072 bytes
Used static DRAM: 12392 bytes ( 168344 available, 6.9% used)
Used static IRAM: 38804 bytes ( 92268 available, 29.6% used)
Flash code: 75004 bytes
Flash rodata: 23780 bytes
Total image size:~ 145908 bytes (.bin may be padded larger)
通过运行stat --format="%s" main/main.c
所有大小均以字节为单位
Test No. | Code | Image | Flash Code | Flash rodata
-------- | -----| ------ | ---------- | ------------
1 | 207 | 146376 | 75408 | 23844
2 | 70 | 146160 | 75240 | 23796
3 | 43 | 145908 | 75004 | 23780
至少有145KB的样板代码才能获得空的主运行。
我怀疑145KB是由许多库组成的，无论您是否使用它们，这些库总是加载到芯片上。其中一些必须是FreeRTOS，WiFi，HTTP等。
我们可以以某种方式减小此大小并仅加载操作所需的最低要求吗？
答案 0 :(得分：2)
您可以通过运行idf.py size-components和idf.py size-files获得更详细的尺寸信息。这是在我的开发环境中“测试3”（即空函数）的结果（请注意，我的Total Image Size已经比您发布的结果稍大了。
Total sizes:
DRAM .data size: 7860 bytes
DRAM .bss size: 4128 bytes
Used static DRAM: 11988 bytes ( 168748 available, 6.6% used)
Used static IRAM: 32706 bytes ( 98366 available, 25.0% used)
Flash code: 76002 bytes
Flash rodata: 32164 bytes
Total image size:~ 148732 bytes (.bin may be padded larger)
Per-archive contributions to ELF file:
Archive File DRAM .data & .bss IRAM Flash code & rodata Total
libc.a 0 0 0 55348 3829 59177
libesp32.a 2132 2351 6767 5976 8076 25302
libfreertos.a 4140 776 12432 0 1653 19001
libdriver.a 76 20 0 4003 7854 11953
libsoc.a 161 4 4953 612 3852 9582
libvfs.a 240 103 0 5464 950 6757
libheap.a 877 4 3095 830 986 5792
libspi_flash.a 24 290 1855 779 890 3838
libefuse.a 16 4 0 1142 2213 3375
libnewlib.a 152 272 766 830 96 2116
libapp_update.a 0 4 109 159 1221 1493
libesp_ringbuf.a 0 0 848 0 209 1057
liblog.a 8 268 429 82 0 787
libhal.a 0 0 515 0 32 547
libpthread.a 8 12 0 256 0 276
libgcc.a 0 0 0 0 160 160
libbootloader_support.a 0 0 0 126 0 126
libm.a 0 0 0 88 0 88
libcxx.a 0 0 0 11 0 11
libxtensa-debug-module.a 0 0 8 0 0 8
libmain.a 0 0 0 5 0 5
(exe) 0 0 0 0 0 0
libmbedcrypto.a 0 0 0 0 0 0
libmbedtls.a 0 0 0 0 0 0
libwpa_supplicant.a 0 0 0 0 0 0
Per-file contributions to ELF file:
Object File DRAM .data & .bss IRAM Flash code & rodata Total
lib_a-vfprintf.o 0 0 0 14193 756 14949
lib_a-svfprintf.o 0 0 0 13838 756 14594
lib_a-svfiprintf.o 0 0 0 9642 1210 10852
lib_a-vfiprintf.o 0 0 0 9945 738 10683
uart.c.obj 44 12 0 2985 7293 10334
tasks.c.obj 12 700 5546 0 531 6789
vfs_uart.c.obj 48 63 0 3680 808 4599
panic.c.obj 2023 5 1989 0 0 4017
esp_err_to_name.c.obj 0 0 0 50 3947 3997
portasm.S.obj 3084 0 484 0 0 3568
lib_a-dtoa.o 0 0 0 3522 13 3535
multi_heap.c.obj 873 0 2277 0 0 3150
intr_alloc.c.obj 8 22 618 1703 722 3073
esp_efuse_utility.c.obj 0 0 0 867 2205 3072
cpu_start.c.obj 0 1 1068 331 1352 2752
queue.c.obj 0 0 2310 0 325 2635
lib_a-mprec.o 0 0 0 2134 296 2430
rtc_clk.c.obj 161 4 2098 0 0 2263
dbg_stubs.c.obj 0 2072 32 108 0 2212
vfs.c.obj 192 40 0 1784 142 2158
rtc_periph.c.obj 0 0 0 0 2080 2080
esp_timer_esp32.c.obj 8 26 1068 262 538 1902
xtensa_vectors.S.obj 8 0 1776 0 36 1820
flash_mmap.c.obj 0 264 1092 114 339 1809
task_wdt.c.obj 53 4 0 1178 548 1783
heap_caps.c.obj 4 0 818 52 617 1491
timers.c.obj 8 56 1006 0 233 1303
cache_utils.c.obj 4 14 749 81 402 1250
soc_memory_layout.c.obj 0 0 0 0 1181 1181
heap_caps_init.c.obj 0 4 0 778 369 1151
port.c.obj 0 16 625 0 493 1134
esp_ota_ops.c.obj 0 4 0 147 965 1116
xtensa_intr_asm.S.obj 1024 0 51 0 0 1075
ringbuf.c.obj 0 0 848 0 209 1057
rtc_time.c.obj 0 0 815 0 198 1013
memory_layout_utils.c.ob 0 0 0 612 393 1005
rtc_init.c.obj 0 0 992 0 0 992
periph_ctrl.c.obj 8 0 0 615 280 903
lib_a-fseeko.o 0 0 0 866 0 866
time.c.obj 0 32 122 703 0 857
clk.c.obj 0 0 64 559 221 844
esp_timer.c.obj 8 16 261 406 134 825
dport_access.c.obj 8 40 444 189 137 818
log.c.obj 8 268 429 82 0 787
rtc_wdt.c.obj 0 0 743 0 0 743
partition.c.obj 0 8 0 522 149 679
ipc.c.obj 0 28 159 283 120 590
locks.c.obj 8 0 485 0 94 587
crosscore_int.c.obj 8 8 193 130 156 495
syscall_table.c.obj 144 240 0 82 0 466
system_api.c.obj 0 0 439 0 0 439
timer.c.obj 16 0 0 112 281 409
int_wdt.c.obj 0 1 91 306 0 398
freertos_hooks.c.obj 8 128 43 216 0 395
esp_app_desc.c.obj 0 0 109 12 256 377
brownout.c.obj 0 0 0 149 201 350
windowspill_asm.o 0 0 311 0 0 311
rtc_module.c.obj 8 8 0 291 0 307
xtensa_context.S.obj 0 0 306 0 0 306
cpu_util.c.obj 0 0 305 0 0 305
dport_panic_highint_hdl. 8 0 242 0 0 250
lib_a-reent.o 0 0 0 232 0 232
lib_a-fopen.o 0 0 0 224 0 224
lib_a-snprintf.o 0 0 0 214 0 214
esp_efuse_api.c.obj 0 4 0 193 0 197
pthread_local_storage.c. 8 4 0 180 0 192
cache_err_int.c.obj 0 0 56 98 0 154
xtensa_intr.c.obj 0 0 108 0 35 143
list.c.obj 0 0 142 0 0 142
syscalls.c.obj 0 0 91 45 0 136
lib_a-assert.o 0 0 0 68 60 128
lib_a-flags.o 0 0 0 127 0 127
bootloader_common.c.obj 0 0 0 126 0 126
lib_a-s_frexp.o 0 0 0 110 0 110
flash_ops.c.obj 20 4 14 62 0 100
lib_a-vprintf.o 0 0 0 94 0 94
lib_a-s_fpclassify.o 0 0 0 88 0 88
lib_a-fiprintf.o 0 0 0 84 0 84
pthread.c.obj 0 8 0 76 0 84
esp_efuse_fields.c.obj 0 0 0 82 0 82
clock.o 0 0 72 0 0 72
reent_init.c.obj 0 0 68 0 2 70
state_asm--restore_extra 0 0 62 0 0 62
state_asm--save_extra_nw 0 0 62 0 0 62
xtensa_vector_defaults.S 0 0 46 0 0 46
lib_a-fseek.o 0 0 0 45 0 45
_divdi3.o 0 0 0 0 40 40
_moddi3.o 0 0 0 0 40 40
_udivdi3.o 0 0 0 0 40 40
_umoddi3.o 0 0 0 0 40 40
xtensa_init.c.obj 0 4 32 0 0 36
interrupts--intlevel.o 0 0 0 0 32 32
esp_efuse_table.c.obj 16 0 0 0 8 24
lib_a-errno.o 0 0 0 10 0 10
pm_esp32.c.obj 0 0 0 8 0 8
int_asm--set_intclear.o 0 0 8 0 0 8
eri.c.obj 0 0 8 0 0 8
cxx_exception_stubs.cpp. 0 0 0 6 0 6
cxx_guards.cpp.obj 0 0 0 5 0 5
hello_world_main.c.obj 0 0 0 5 0 5
FreeRTOS-openocd.c.obj 4 0 0 0 0 4
dummy_main_src.c.obj 0 0 0 0 0 0
bootloader_flash.c.obj 0 0 0 0 0 0
bootloader_random.c.obj 0 0 0 0 0 0
bootloader_sha.c.obj 0 0 0 0 0 0
esp_image_format.c.obj 0 0 0 0 0 0
flash_partitions.c.obj 0 0 0 0 0 0
lib_a-fputs.o 0 0 0 0 0 0
lib_a-printf.o 0 0 0 0 0 0
lib_a-putc.o 0 0 0 0 0 0
lib_a-putchar.o 0 0 0 0 0 0
lib_a-puts.o 0 0 0 0 0 0
lib_a-sprintf.o 0 0 0 0 0 0
lib_a-strerror.o 0 0 0 0 0 0
lib_a-u_strerr.o 0 0 0 0 0 0
lib_a-xpg_strerror_r.o 0 0 0 0 0 0
gpio.c.obj 0 0 0 0 0 0
hw_random.c.obj 0 0 0 0 0 0
pm_locks.c.obj 0 0 0 0 0 0
_addsubdf3.o 0 0 0 0 0 0
_cmpdf2.o 0 0 0 0 0 0
_divdf3.o 0 0 0 0 0 0
_fixdfsi.o 0 0 0 0 0 0
_floatdidf.o 0 0 0 0 0 0
_floatsidf.o 0 0 0 0 0 0
_muldf3.o 0 0 0 0 0 0
_popcountsi2.o 0 0 0 0 0 0
platform.c.obj 0 0 0 0 0 0
platform_util.c.obj 0 0 0 0 0 0
sha256.c.obj 0 0 0 0 0 0
esp_mem.c.obj 0 0 0 0 0 0
gpio_periph.c.obj 0 0 0 0 0 0
spi_flash_rom_patch.c.ob 0 0 0 0 0 0
md5-internal.c.obj 0 0 0 0 0 0
从库的角度来看，主要贡献者是libc，它是C标准库。尽管您可能可以挑选一些功能然后从中删除其他功能，但我认为没有人会推荐这样做。
下一步是libesp32，它提供诸如start_cpu0()之类的关键功能。同样，如果您确实愿意，您可以只挑选所需的功能。
您可以通过查找.a文件（例如find build -name libesp32.a，然后在找到的路径上运行nm build/esp-idf/esp32/libesp32.a来找出库提供的内容。
第二张表列出了相同的大小数据，但按源文件而不是按库进行了划分。