logging: Add ratelimited variants

These are helpful for logging in data-path, not to overwhelm the
console but still keep the user informed about the issues.

This is similar to printk_ratelimited in Linux kernel.

Signed-off-by: Chaitanya Tata <[email protected]>

Author: krish2718

doc/releases/release-notes-4.3.rst

@@ -65,6 +65,23 @@ New APIs and options
 
 .. zephyr-keep-sorted-start re(^\* \w)
 
+* :c:macro:`LOG_ERR_RATELIMITED` - Rate-limited error logging macro (convenience)
+* :c:macro:`LOG_WRN_RATELIMITED` - Rate-limited warning logging macro (convenience)
+* :c:macro:`LOG_INF_RATELIMITED` - Rate-limited info logging macro (convenience)
+* :c:macro:`LOG_DBG_RATELIMITED` - Rate-limited debug logging macro (convenience)
+* :c:macro:`LOG_HEXDUMP_ERR_RATELIMITED` - Rate-limited error hexdump macro (convenience)
+* :c:macro:`LOG_HEXDUMP_WRN_RATELIMITED` - Rate-limited warning hexdump macro (convenience)
+* :c:macro:`LOG_HEXDUMP_INF_RATELIMITED` - Rate-limited info hexdump macro (convenience)
+* :c:macro:`LOG_HEXDUMP_DBG_RATELIMITED` - Rate-limited debug hexdump macro (convenience)
+* :c:macro:`LOG_ERR_RATELIMITED_RATE` - Rate-limited error logging macro (explicit rate)
+* :c:macro:`LOG_WRN_RATELIMITED_RATE` - Rate-limited warning logging macro (explicit rate)
+* :c:macro:`LOG_INF_RATELIMITED_RATE` - Rate-limited info logging macro (explicit rate)
+* :c:macro:`LOG_DBG_RATELIMITED_RATE` - Rate-limited debug logging macro (explicit rate)
+* :c:macro:`LOG_HEXDUMP_ERR_RATELIMITED_RATE` - Rate-limited error hexdump macro (explicit rate)
+* :c:macro:`LOG_HEXDUMP_WRN_RATELIMITED_RATE` - Rate-limited warning hexdump macro (explicit rate)
+* :c:macro:`LOG_HEXDUMP_INF_RATELIMITED_RATE` - Rate-limited info hexdump macro (explicit rate)
+* :c:macro:`LOG_HEXDUMP_DBG_RATELIMITED_RATE` - Rate-limited debug hexdump macro (explicit rate)
+
 .. zephyr-keep-sorted-stop
 
 New Boards
@@ -90,9 +107,27 @@ New Samples
   Same as above for boards and drivers, this will also be recomputed at the time of the release.
  Just link the sample, further details go in the sample documentation itself.
 
+Libraries / Subsystems
+**********************
+
+* Logging:
+
+  * Added hybrid rate-limited logging macros to prevent log flooding when messages are generated frequently.
+    The system provides both convenience macros (using default rate from :kconfig:option:`CONFIG_LOG_RATELIMIT_INTERVAL_MS`)
+    and explicit rate macros (with custom rate parameter). This follows Linux's ``printk_ratelimited`` pattern
+    while providing more flexibility. The rate limiting is per-macro-call-site, meaning that each unique call
+    to a rate-limited macro has its own independent rate limit. Rate-limited logging can be globally enabled/disabled
+    via :kconfig:option:`CONFIG_LOG_RATELIMIT_ENABLE`. For more details, see :ref:`logging_ratelimited`.
+
 Other notable changes
 *********************
 
+* Added rate-limited logging functionality to prevent log flooding when messages are generated frequently.
+  This includes 16 new macros (8 convenience macros using default rate and 8 explicit rate macros)
+  for all log levels and hexdump variants. The feature can be globally enabled/disabled via
+  ``CONFIG_LOG_RATELIMIT_ENABLE`` and the default rate configured via
+  ``CONFIG_LOG_RATELIMIT_INTERVAL_MS``. For more details, see :ref:`logging_ratelimited`.
+
 ..
   Any more descriptive subsystem or driver changes. Do you really want to write
   a paragraph or is it enough to link to the api/driver/Kconfig/board page above?

doc/services/logging/index.rst

@@ -32,6 +32,7 @@ Summary of the logging features:
 - Support for logging floating point variables and long long arguments.
 - Built-in copying of transient strings used as arguments.
 - Support for multi-domain logging.
+- Rate-limited logging macros to prevent log flooding when messages are generated frequently.
 
 Logging API is highly configurable at compile time as well as at run time. Using
 Kconfig options (see :ref:`logging_kconfig`) logs can be gradually removed from
@@ -59,6 +60,16 @@ The warning level also exposes the following additional macro:
 
 - :c:macro:`LOG_WRN_ONCE` for warnings where only the first occurrence is of interest.
 
+Rate-limited logging macros are also available for all severity levels to prevent log flooding:
+
+- ``LOG_X_RATELIMITED`` for rate-limited standard printf-like messages using default rate, e.g. :c:macro:`LOG_ERR_RATELIMITED`.
+- ``LOG_X_RATELIMITED_RATE`` for rate-limited standard printf-like messages with custom rate, e.g. :c:macro:`LOG_ERR_RATELIMITED_RATE`.
+- ``LOG_HEXDUMP_X_RATELIMITED`` for rate-limited data dumping using default rate, e.g. :c:macro:`LOG_HEXDUMP_WRN_RATELIMITED`.
+- ``LOG_HEXDUMP_X_RATELIMITED_RATE`` for rate-limited data dumping with custom rate, e.g. :c:macro:`LOG_HEXDUMP_WRN_RATELIMITED_RATE`.
+
+The convenience macros use the default rate specified by ``CONFIG_LOG_RATELIMIT_INTERVAL_MS``,
+while the explicit rate macros take a rate parameter (in milliseconds) that specifies the minimum interval between log messages.
+
 There are two configuration categories: configurations per module and global
 configuration. When logging is enabled globally, it works for modules. However,
 modules can disable logging locally. Every module can specify its own logging
@@ -341,6 +352,88 @@ If logs are processed from a thread (user or internal) then it is possible to en
 a feature which will wake up processing thread when certain amount of log messages are
 buffered (see :kconfig:option:`CONFIG_LOG_PROCESS_TRIGGER_THRESHOLD`).
 
+.. _logging_ratelimited:
+
+Rate-limited logging
+********************
+
+Rate-limited logging macros provide a way to prevent log flooding when messages are
+generated frequently. These macros ensure that log messages are not output more
+frequently than a specified interval, similar to Linux's ``printk_ratelimited``
+functionality.
+
+The rate-limited logging system provides two types of macros:
+
+**Convenience macros (using default rate):**
+- :c:macro:`LOG_ERR_RATELIMITED` - Rate-limited error messages
+- :c:macro:`LOG_WRN_RATELIMITED` - Rate-limited warning messages
+- :c:macro:`LOG_INF_RATELIMITED` - Rate-limited info messages
+- :c:macro:`LOG_DBG_RATELIMITED` - Rate-limited debug messages
+- :c:macro:`LOG_HEXDUMP_ERR_RATELIMITED` - Rate-limited error hexdump
+- :c:macro:`LOG_HEXDUMP_WRN_RATELIMITED` - Rate-limited warning hexdump
+- :c:macro:`LOG_HEXDUMP_INF_RATELIMITED` - Rate-limited info hexdump
+- :c:macro:`LOG_HEXDUMP_DBG_RATELIMITED` - Rate-limited debug hexdump
+
+**Explicit rate macros (with custom rate):**
+- :c:macro:`LOG_ERR_RATELIMITED_RATE` - Rate-limited error messages with custom rate
+- :c:macro:`LOG_WRN_RATELIMITED_RATE` - Rate-limited warning messages with custom rate
+- :c:macro:`LOG_INF_RATELIMITED_RATE` - Rate-limited info messages with custom rate
+- :c:macro:`LOG_DBG_RATELIMITED_RATE` - Rate-limited debug messages with custom rate
+- :c:macro:`LOG_HEXDUMP_ERR_RATELIMITED_RATE` - Rate-limited error hexdump with custom rate
+- :c:macro:`LOG_HEXDUMP_WRN_RATELIMITED_RATE` - Rate-limited warning hexdump with custom rate
+- :c:macro:`LOG_HEXDUMP_INF_RATELIMITED_RATE` - Rate-limited info hexdump with custom rate
+- :c:macro:`LOG_HEXDUMP_DBG_RATELIMITED_RATE` - Rate-limited debug hexdump with custom rate
+
+The convenience macros use the default rate specified by :kconfig:option:`CONFIG_LOG_RATELIMIT_INTERVAL_MS`
+(5000ms by default). The explicit rate macros take a rate parameter (in milliseconds) that specifies
+the minimum interval between log messages. The rate limiting is per-macro-call-site, meaning
+that each unique call to a rate-limited macro has its own independent rate limit.
+
+Example usage:
+
+.. code-block:: c
+
+    #include <zephyr/logging/log.h>
+    #include <zephyr/kernel.h>
+
+    LOG_MODULE_REGISTER(my_module, CONFIG_LOG_DEFAULT_LEVEL);
+
+    void process_data(void)
+    {
+    /* Convenience macros using default rate (CONFIG_LOG_RATELIMIT_INTERVAL_MS) */
+    LOG_WRN_RATELIMITED("Data processing warning: %d", error_code);
+    LOG_ERR_RATELIMITED("Critical error occurred: %s", error_msg);
+    LOG_INF_RATELIMITED("Processing status: %d items", item_count);
+    LOG_HEXDUMP_WRN_RATELIMITED(data_buffer, data_len, "Data buffer:");
+
+    /* Explicit rate macros with custom intervals */
+    LOG_WRN_RATELIMITED_RATE(1000, "Fast rate warning: %d", error_code);
+    LOG_ERR_RATELIMITED_RATE(30000, "Slow rate error: %s", error_msg);
+    LOG_INF_RATELIMITED_RATE(2000, "Custom rate status: %d items", item_count);
+    LOG_HEXDUMP_ERR_RATELIMITED_RATE(5000, data_buffer, data_len, "Error data:");
+    }
+
+Rate-limited logging is particularly useful for:
+
+- Error conditions that might occur frequently but don't need to flood the logs
+- Status updates in tight loops or high-frequency callbacks
+- Debug information that could overwhelm the logging system
+- Network or I/O operations that might fail repeatedly
+
+Configuration
+==============
+
+Rate-limited logging can be configured using the following Kconfig options:
+
+- :kconfig:option:`CONFIG_LOG_RATELIMIT_ENABLE` - Master switch to enable/disable rate-limited logging
+- :kconfig:option:`CONFIG_LOG_RATELIMIT_INTERVAL_MS` - Default interval for convenience macros (5000ms)
+
+When :kconfig:option:`CONFIG_LOG_RATELIMIT_ENABLE` is disabled, all rate-limited macros expand to no-ops,
+ensuring clean compilation without any runtime overhead.
+
+The rate limiting is implemented using static variables and :c:func:`k_uptime_get_32`
+to track the last log time for each call site.
+
 .. _logging_panic:
 
 Logging panic
@@ -790,6 +883,8 @@ Benchmark
 Benchmark numbers from :zephyr_file:`tests/subsys/logging/log_benchmark` performed
 on ``qemu_x86``. It is a rough comparison to give a general overview.
 
+For testing rate-limited logging functionality, see :zephyr_file:`tests/subsys/logging/log_ratelimited`.
+
 +--------------------------------------------+------------------+
 | Feature                                    |                  |
 +============================================+==================+