> ## Documentation Index > Fetch the complete documentation index at: https://docs.cockroachlabs.com/llms.txt > Use this file to discover all available pages before exploring further. # Automatic CPU Profiler This feature automatically captures CPU profiles, which can make it easier to investigate and troubleshoot spikes in CPU usage or erratic CPU load on certain nodes. A CPU profile shows the functions that use the most CPU time, sampled over a window of time. You can collect a CPU Profile manually on the [Advanced Debug page](/docs/stable/ui-debug-pages.md). However, it may be difficult to manually capture a profile of a short CPU spike at the right point in time. Automatic CPU profile capture enables the investigation of CPU load in this and other cases, such as periodic high CPU. ## Configuration You can configure automatic CPU profile capture with the following [cluster settings](/docs/stable/cluster-settings.md): | Cluster Setting | Description | Default Value | | - | - | - | | `server.cpu_profile.cpu_usage_combined_threshold` | The baseline threshold of CPU usage at which a CPU profile is taken from a node. This value is a percentage. | `65` | | `65` | | | | `server.cpu_profile.interval` | The period of time after which the [high-water mark](#high-water-mark-threshold) resets to the baseline value. | `20m0s` (20 minutes) | | `server.cpu_profile.duration` | The length of time a CPU profile is taken. | `10s` (10 seconds) | | `server.cpu_profile.total_dump_size_limit` | Maximum combined disk size for preserving CPU profiles. | `128 MiB` (128 Mebibytes) | ## High-water mark threshold The Automatic CPU Profiler runs asynchronously in the background. After every second, the Automatic CPU Profiler checks if the CPU usage exceeds the high-water mark threshold. If so, it captures a CPU profile. If a profile capture is already in progress, a second profile is not taken. The Automatic CPU Profiler uses the configuration options to determine the high-water mark threshold. For example, with `duration` set to `10s` , `interval` set to `20m0s`, and `cpu_usage_combined_threshold` set to `65`: * At `time0` the CPU usage polled is `70` percent. This exceeds the baseline threshold of `65`, so a `10s` profile is captured and the high-water mark threshold becomes `70`. * After the `10s` profile capture, the Automatic CPU Profiler continues to check every second if the CPU usage now exceeds `70` percent. * At `time1` the CPU usage polled is `80` percent, another profile is taken for `10s`, and the high-water mark threshold becomes `80`. * At `time2`, the `20m0s` interval after `time0`, the high-water mark threshold is reset to the baseline threshold of `65`. * The Automatic CPU Profiler continues to poll every second, and captures a profile whenever CPU usage exceeds the high-water mark threshold. ## Accessing CPU profiles * The Automatic CPU Profiler saves the captured CPU profiles to disk on each node's file system in the [logging directory](/docs/stable/configure-logs.md#logging-directory). The default path is `cockroach-data/logs/pprof_dump`. * The only way to get these CPU profiles is to access the node file system. * Enabling the Automatic CPU Profiler does **not** add CPU profiles to [debug zips](/docs/stable/cockroach-debug-zip.md). ## Overhead Enabling the automatic CPU profile capture on a cluster will add overhead to the cluster in the form of potential increases in latency and CPU usage. * Monitor the following metrics: * [P99 latency](/docs/stable/ui-sql-dashboard.md#service-latency-sql-99th-percentile) * P50 latency by creating a [custom chart](/docs/stable/ui-custom-chart-debug-page.md) for the `sql.exec.latency-p50` metric * [CPU usage](/docs/stable/ui-hardware-dashboard.md#cpu-percent) ## See also * [Automatic Go Execution Tracer](/docs/stable/automatic-go-execution-tracer.md)