add calibrate resource error and metrics description

dashboard/dashboard-resource-manager.md

@@ -57,7 +57,9 @@ Before resource planning, you need to know the overall capacity of the cluster.
 
     - When the time window range does not fall between 10 minutes and 24 hours, the following error is displayed `ERROR 1105 (HY000): the duration of calibration is too short, which could lead to inaccurate output. Please make the duration between 10m0s and 24h0m0s`.
 
-    - When the workload within the time window is too low, the following error is displayed `ERROR 1105 (HY000): The workload in selected time window is too low, with which TiDB is unable to reach a capacity estimation; please select another time window with higher workload, or calibrate resource by hardware instead` is displayed.
+    - The monitoring metrics for the [capacity estimation based on the actual workload](/sql-statements/sql-statement-calibrate-resource.md#estimate-capacity-based-on-actual-workload) feature include `tikv_cpu_quota`, `tidb_server_maxprocs`, `resource_manager_resource_unit`, and `process_cpu_usage`. If the CPU quota monitoring data is empty, there will be an error with the corresponding monitoring metric name, for example, `Error 1105 (HY000): There is no CPU quota metrics, metrics 'tikv_cpu_quota' is empty`.
+
+    - If the workload in the time window is too low, or the `resource_manager_resource_unit` and `process_cpu_usage` monitoring data is missing, an error will be reported `Error 1105 (HY000): The workload in selected time window is too low, with which TiDB is unable to reach a capacity estimation; please select another time window with higher workload, or calibrate resource by hardware instead`. In addition, because TiKV does not monitor CPU utilization on macOS, it does not support capacity estimation based on the actual workload, and will also report this error.
 
   You can select an appropriate time range using **CPU Usage** in the [Metrics](#metrics) section.
 

grafana-resource-control-dashboard.md

@@ -23,6 +23,8 @@ This document describes some key monitoring metrics displayed on the Resource Co
 - RRU Per Query: the average number of Read Request Units consumed by each SQL statement per second. It is obtained by dividing the above RRU metric by the number of SQL statements executed per second.
 - WRU: the Write Request Unit consumption information of each resource group, calculated in real time. `total` is the sum of the Write Request Units consumed by all Resource Groups.
 - WRU Per Query: the average number of Write Request Units consumed by each SQL statement per second. It is obtained by dividing the above WRU metric by the number of SQL statements executed per second.
+- Available RU: the available tokens in the RU token bucket of each resource group. When it is `0`, this resource group consumes tokens at the rate of `RU_PER_SEC` and can be considered to be in a rate-limited state.
+- Query Max Duration: the maximum Query Duration in terms of resource groups.
 
 ## Metrics about resources
 

sql-statements/sql-statement-calibrate-resource.md

@@ -47,6 +47,10 @@ If your application is already running in a production environment, or you can r
 - The time window ranges from 10 minutes to 24 hours.
 - In the specified time window, if the CPU utilization of TiDB and TiKV is too low, you cannot estimate the capacity.
 
+> **Note:**
+>
+> TiKV does not monitor CPU usage metrics on macOS. It does not support capacity estimation based on the actual workload on macOS.
+
 ### Estimate capacity based on hardware deployment
 
 This method mainly estimates capacity based on the current cluster configuration, combined with the empirical values observed for different workloads. Because different types of workloads require different ratios of hardware, the output capacity of the same configuration of hardware might be different. The `WORKLOAD` parameter here accepts the following different workload types. The default value is `TPCC`.
@@ -95,7 +99,14 @@ CALIBRATE RESOURCE START_TIME '2023-04-18 08:00:00' DURATION '9m';
 ERROR 1105 (HY000): the duration of calibration is too short, which could lead to inaccurate output. Please make the duration between 10m0s and 24h0m0s
 ```
 
-When the workload within the time window is too low, an error occurs.
+The monitoring metrics for the [capacity estimation based on the actual workload](#estimate-capacity-based-on-actual-workload) feature include `tikv_cpu_quota`, `tidb_server_maxprocs`, `resource_manager_resource_unit`, and `process_cpu_usage`. If the CPU quota monitoring data is empty, there will be an error with the corresponding monitoring metric name, as shown in the following example:
+
+```sql
+CALIBRATE RESOURCE START_TIME '2023-04-18 08:00:00' DURATION '60m';
+Error 1105 (HY000): There is no CPU quota metrics, metrics 'tikv_cpu_quota' is empty
+```
+
+If the workload in the time window is too low, or the `resource_manager_resource_unit` and `process_cpu_usage` monitoring data is missing, the following error will be reported. In addition, because TiKV does not monitor CPU utilization on macOS, it does not support capacity estimation based on the actual workload, and will also report this error.
 
 ```sql
 CALIBRATE RESOURCE START_TIME '2023-04-18 08:00:00' DURATION '60m';