Changes based on review comments

Author: anton-bobkov

ydb/docs/en/core/dev/troubleshooting/performance/hardware/_assets/embedded-ui-cpu-system-pool.png

@@ -1,4 +1,16 @@
-1. Analyze CPU utilization in all pools:
+1. Use **Diagnostics** in the [Embedded UI](../../../../../reference/embedded-ui/index.md) to analyze CPU utilization in all pools:
+
+    1. In the [Embedded UI](../../../../../reference/embedded-ui/index.md), go to the **Databases** tab and click on the database.
+
+    1. On the **Navigation** tab, ensure the required database is selected.
+
+    1. Open the **Diagnostics** tab.
+
+    1. On the **Info** tab, click the **CPU** button and see if any pools show high CPU usage.
+
+        ![](../_assets/embedded-ui-cpu-system-pool.png)
+
+1. Use Grafana charts to analyze CPU utilization in all pools:
 
     1. Open the **[CPU](../../../../../reference/observability/metrics/grafana-dashboards.md#cpu)** dashboard in Grafana.
 

ydb/docs/en/core/dev/troubleshooting/performance/hardware/_includes/cpu-bottleneck.md

@@ -4,6 +4,12 @@ If [swap](https://en.wikipedia.org/wiki/Memory_paging#Unix_and_Unix-like_systems
 
 If swap is enabled, insufficient memory may cause the database to rely heavily on disk I/O, which is significantly slower than accessing data directly from memory.
 
+{% note warning %}
+
+If {{ ydb-short-name }} nodes are running on servers with swap enabled, disable it. {{ ydb-short-name }} is a distributed system, so if a node restarts due to lack of memory, the client will simply connect to another node and continue accessing data as if nothing happened. Swap would allow the query to continue on the same node but with degraded performance from increased disk I/O, which is generally less desirable.
+
+{% endnote %}
+
 Even though the reasons and mechanics of performance degradation due to insufficient memory might differ, the symptoms of increased latencies during query execution and data retrieval are similar in all cases.
 
 Additionally, which components within the  {{ ydb-short-name }} process consume memory may also be significant.
@@ -46,6 +52,7 @@ Consider the following solutions for addressing insufficient memory:
 
 - If the load on {{ ydb-short-name }} has increased due to new usage patterns or increased query rate, try optimizing the application to reduce the load on {{ ydb-short-name }} or add more {{ ydb-short-name }} nodes.
 
-- If the load on {{ ydb-short-name }} has not changed but nodes are still restarting, consider adding more {{ ydb-short-name }} nodes or raising the hard memory limit for the nodes.
+- If the load on {{ ydb-short-name }} has not changed but nodes are still restarting, consider adding more {{ ydb-short-name }} nodes or raising the hard memory limit for the nodes. For more information about memory management in {{ ydb-short-name }}, see [{#T}](../../../../reference/configuration/index.md#memory-controller).
+
+
 
-Additionally, if {{ ydb-short-name }} nodes are running on servers with swap enabled, disable it. {{ ydb-short-name }} is a distributed system, so if a node restarts due to lack of memory, the client will simply connect to another node and continue accessing data as if nothing happened. Swap would allow the query to continue on the same node but with degraded performance from increased disk I/O, which is generally less desirable.

ydb/docs/en/core/dev/troubleshooting/performance/hardware/insufficient-memory.md

@@ -31,7 +31,7 @@ Database performance issues can be classified into several categories based on t
 
 - **[Server hardware issues](infrastructure/hardware.md)**. Malfunctioning CPU, memory modules, and network cards, until replaced, significantly impact database performance or lead to the unavailability of the affected server.
 
-### Insufficient resources
+### Insufficient resource issues
 
 These issues refer to situations when the workload demands more physical resources — such as CPU, memory, disk space, and network bandwidth — than allocated to a database. In some cases, suboptimal allocation of resources, for example misconfigured [control groups (cgroups)](https://en.wikipedia.org/wiki/Cgroups) or [actor system pools](../../../concepts/glossary.md#actor-system-pool), may also result in insufficient resources for {{ ydb-short-name }} and increase query latencies even though physical hardware resources are still available on the database server.
 

ydb/docs/en/core/dev/troubleshooting/performance/index.md

@@ -1,25 +1,25 @@
 items:
-  - name: Infrastructure issues
+  - name: Infrastructure
     include:
       mode: link
       path: infrastructure/toc_p.yaml
-  - name: Reaching resource limits
+  - name: Insufficient resources
     include:
       mode: link
       path: hardware/toc_p.yaml
-  - name: OS issues
+  - name: OS
     include:
       mode: link
       path: system/toc_p.yaml
-  - name: YDB configuration issues
+  - name: YDB configuration
     include:
       mode: link
       path: ydb/toc_p.yaml
-  - name: Schema design issues
+  - name: Schema design
     include:
       mode: link
       path: schemas/toc_p.yaml
-  - name: Client application issues
+  - name: Client application
     include:
       mode: link
       path: queries/toc_p.yaml