Help with Ring Buffer Implementation

RE: Help with Ring Buffer Implementation

Elfving — Wed, 17 Sep 2025 07:10:07 GMT

Ah okay. Thanks for letting me know! 🙂 Even though that wasn't on my list of suggestions I hope you'll let us know if there is anything else you need help with in the future.

Regards,

Elfving

RE: Help with Ring Buffer Implementation

Luis Santos — Tue, 16 Sep 2025 17:37:08 GMT

Sorry for the late response, Elfving.

I think the issue was related to the length of my struct. Once I decreased the struct length, I stopped having those problems.

Thanks a lot for your support!

RE: Help with Ring Buffer Implementation

Elfving — Fri, 22 Aug 2025 13:29:50 GMT

Hi again,

since you haven't replied I assume you figured it out?

Regards,

Elfving

RE: Help with Ring Buffer Implementation

Elfving — Wed, 20 Aug 2025 15:03:11 GMT

Hello Luis,

I'll have to get back to you on this later this week, though I see you already have some pointers here. Another thing to make sure is that you are feeding the right data item to ring_buf_item_put(), and that you are not mixing up item and data mode. You can see more here.

Regards,

Elfving

RE: Help with Ring Buffer Implementation

hmolesworth — Tue, 19 Aug 2025 17:25:40 GMT

At first sight it looks like put and get applies to a single element queue filterSrvRingBuffer instead of filterSrvBufferStorage; that single-element queue would fill up pretty quickly. There is also (perhaps benign) alignment issue between bytes and struct; I would suggest something like:

// Align of size of largest struct field, probably 32-bit but use 64-bit:
static uint8_t filterSrvBufferStorage[FILTER_SRV_BUFFER_SIZE_BYTES] __attribute__((section(".bss"), aligned(8), used));

I would personally order the struct and then compact to reduce storage and get/put overhead, although that can slow access to individual fields within the struct outside of the queue:

#pragma pack(1) //ensure byte by byte struct packing
typedef struct
{
    uint16_t addr;
    uint8_t valid_addr;        /// <<== move all known odd-byte fields to end of struct
    filterSrvSensorType_t analyzing_type;
    emaFilterContext_t ema_context;
    temaFilterContext_t tema_context;
    kalmanFilterContext_t kalman_context;
    filterSrvSensorContext_t ble_sensor_context;
    filterSrvSensorContext_t lora_sensor_context;
} filterSrvContext_t;
#pragma pack()

The underlying queue uses 32-bit values so best to ensure the struct has overall n*4 bytes.