Memory profiling¶

The memory profiling functionality allows tracing of different memory regions. To use it, enable CONFIG_ZPL_MEMORY_PROFILING in the Kconfig.

Memory types¶

The profiling tool currently supports the following memory regions in Zephyr:

• Stack

• Heaps

• k_heaps

• Memory Slabs

Memory event¶

The memory tracing tool uses custom events. Those events contain information about the memory regions at a point in time.

Common Trace Format¶

The memory event is a packed structure, described below. It contains information about:

• timestamp - the timestamp at which the event occurred

• id - id of the event defined as 0xEE

• memory_region - the profiled memory region (stack, heap, etc.)

• memory_addr - memory address, which serves as memory region identifier

• used, unused - Used and unused number of bytes

• for_thread_id - ID of the thread associated with the memory region or 0 otherwise

typedef struct __packed {
    uint32_t timestamp;
    uint8_t id;
    enum zpl_memory_region memory_region;
    uintptr_t memory_addr;
    uint32_t used;
    uint32_t unused;
    uint32_t for_thread_id;
} zpl_memory_event_t;

The available memory regions are defined as an enum:

enum zpl_memory_region {
    ZPL_STACK = 0,
    ZPL_HEAP,
    ZPL_K_HEAP,
    ZPL_MEM_SLAB,
};

Plaintext¶

When using a CONFIG_ZPL_TRACE_FORMAT_PLAINTEXT format, the memory events are printed in plaintext. The events contain the same information as in the CTF format, but in human readable form. The example shown below, contains a series of memory events of different memory regions.

• zpl_memory_event - event name

• stack, heap, etc. - memory region

• 0x20011748 - memory address

• 80B 432B - used and unused memory size (in order)

• 536936848 - thread ID

zpl_memory_event stack (0x20011748) 80B 432B 536936848
zpl_memory_event stack (0x20011348) 48B 976B 536936848
zpl_memory_event stack (0x20012148) 48B 272B 536937024
zpl_memory_event stack (0x20012288) 280B 744B 536937200
zpl_memory_event heap (0x20010048) 28B 164B 0
zpl_memory_event heap (0x2001005c) 12B 940B 0
zpl_memory_event heap (0x200106ac) 0B 47132B 0
zpl_memory_event k_heap (0x20010048) 28B 164B 0
zpl_memory_event k_heap (0x2001005c) 12B 940B 0
zpl_memory_event mem_slab (0x2001002c) 256B 7936B 0