Timers period changed for some reason

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In my programming, I create some timers. but it exists a strange situation between 2 particular timers(maybe there are some connections). For details, a timer called A is running,
the A timer period is 1 second and it will get the Linux system time and show it in the screen. So it should updates per second. Then I start the timer B, B’s period is also 1s, timer B is to read some record files and to show 10 records. The strange things occured, if I resume the timer B, the timer A’s period seems changed to 5s, so the display updates per 5 seconds. If I stop the timer B, the timer A runs OK again. Actually, I create other timers and make sure each time there are 2 timers is running(A and other one). And only when timer A and B is runing , the timer A affected. It puzzles me a lot. Because the same timer design is runs well in LVGL V 6.0.2.

What MCU/Processor/Board and compiler are you using?

What LVGL version are you using?


What do you want to achieve?

What have you tried so far?

Code to reproduce

Add a code snippet which can run in the simulator. It should contain only the relevant code that compiles without errors when separated from your main code base.

The code block(s) should be formatted like:

/* this is timer A */
static void TimeRefresh1sTaskCallBack(lv_timer_t* timer)

    /* get system alarm events */
    g_Event.LastEventCnt = g_Event.HMIEvent.cnt;

    /* 清除缓存 */
    memset(s_MenuBarRuntime.YMDCache, 0, sizeof(s_MenuBarRuntime.YMDCache));
    memset(s_MenuBarRuntime.DMSCache, 0, sizeof(s_MenuBarRuntime.DMSCache));

    /* get time*/
    time_t time_seconds = time(0);

    localtime_r(&time_seconds, &nowTime);

    snprintf(s_MenuBarRuntime.YMDCache, MAX_HMI_STRLEN, "%02d-%02d-%02d",
            nowTime.tm_year + 1900, nowTime.tm_mon + 1, nowTime.tm_mday);
    snprintf(s_MenuBarRuntime.DMSCache, MAX_HMI_STRLEN, "%02d:%02d:%02d",
            nowTime.tm_hour, nowTime.tm_min, nowTime.tm_sec);

/*update the timer label, it should update per second*/
    lv_label_set_text_static(s_MenuBarObj.YearMonthDay, s_MenuBarRuntime.YMDCache);
    lv_label_set_text_static(s_MenuBarObj.HourMinSec, s_MenuBarRuntime.DMSCache);

    lv_obj_align_to(s_MenuBarObj.YearMonthDay, lv_scr_act(),
                        LV_ALIGN_BOTTOM_LEFT, 10, 0);
    lv_obj_align_to(s_MenuBarObj.HourMinSec, lv_scr_act(),
                        LV_ALIGN_BOTTOM_LEFT, 18, -20);

/* this is timer B */
static void soe_time_cb(lv_timer_t* timer)
    if (!s_soeRun.soeReq)
        uint32_t tmpNum = s_soeRun.soeNum;

        /* record updates */
        if (tmpNum != s_soeRun.soeNum)
            s_soeRun.soeNum = tmpNum;

            return;// at most time, the timer will execute here and return ,the code below will not execute

    /* 如果是发了但是还未收到回复的话,则不需要再度更新SOE数目 */
    GET_STATUS_T ret = GetSOE(&g_SOE);

    /* 更新收到的话则刷新表格 */
    if (GET_OK_UPDATED == ret)
        /* 重新计算总页面数并发送SOE请求消息队列 */

        /* 接收到SOE信息后再重置按钮,从而保持数据刷新和控件显示同步 */


        s_soeRun.soeReq = false;
    /* 未更新成功需要进行处理 */

        /* 如果10s都没有更新成功,结束本次更新,重新获取SOE的总数 */
        if (s_soeRun.soeUpdateErrCnt > 10)
            s_soeRun.soeUpdateErrCnt = 0;
            s_soeRun.soeReq = false;

Screenshot and/or video

If possible, add screenshots and/or videos about the current state.

It seems the reason is in timer B, it will show the record in labels, the labels I created all is set long mode LV_LABEL_LONG_SCROLL_CIRCULAR and in fact 20 labels will show the long text and present the scroll effects. I cancel the long mode setting then it doesn’t affect the timer A。So how the scroll effect will affected the labels?

Is it possible that the execution of Timer B takes a lot of time?
Please measure it and the execution time of lv_timer_handler as well.

No, the execution of B does not takes a lot of time.At most time, It just open a file (195 KB)then judge the conditions. Actually, the timer B will show 70 labels, and when 20 labels is in the long mode(I mean the text is long then label’s width and the text is scorlling), the timer A’s period becomes 5 seconds. when 10 labels in the long mode it become 2 seconds. So it’s seems that if there are 10 labels is in the long mode and the text is all scorlling it will influenced the timer A. Maybe you can do a little test.

Where/how do you call lv_timer_inc(x)? If called right after lv_timer_handler() the timing can be messed up if the execution on lv_timer_handler takes more time.

You can also set LV_TICK_CUSTOM_SYS_TIME_EXPR to use a custom function that tell the elapsed time in milliseconds.