[Bugfix] Fix incorrect kv cache metrics in grafana.json

[fangpings]

Purpose

Current grafana.json is using an outdated prometheus metrics name gpu_cache_usage_perc. The lastest metrics is named kv_cache_usage_perc. See here

Test Plan

Verified in my own grafana dashboard

Test Result

Before

After

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[mergify]

Documentation preview: https://vllm--27133.org.readthedocs.build/en/27133/

[gemini-code-assist]

Code Review

This pull request updates the grafana.json file to use the correct Prometheus metric name for GPU cache usage. The old metric name gpu_cache_usage_perc is replaced with the new metric name kv_cache_usage_perc. This change ensures that the Grafana dashboard accurately reflects the current metrics being exposed by vLLM.

[gemini-code-assist]

The metric name vllm:gpu_cache_usage_perc is outdated and should be updated to vllm:kv_cache_usage_perc to align with the latest metrics. This discrepancy could lead to incorrect monitoring and alerting.

It's critical to ensure that monitoring dashboards use the correct metric names to provide accurate insights into system performance and resource utilization.

          "expr": "vllm:kv_cache_usage_perc{model_name=\"$model_name\"}"

[markmc]

Thank you!

Just need to fix the DCO issue:

always include Signed-off-by: Author Name [email protected] in every commit message

Since you'll be making that update, would you mind also searching and replacing in examples/online_serving/dashboards/perses/ too? No need to test

[fangpings]

Thank you!

Just need to fix the DCO issue:

always include Signed-off-by: Author Name [email protected] in every commit message

Since you'll be making that update, would you mind also searching and replacing in examples/online_serving/dashboards/perses/ too? No need to test

Thanks. I replaced occurrence under that folder too.