add the codes to check AMD Instinct GPU number

[zhangnju]

Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.

Purpose

LMcache PD example needs at leaest 2 GPUs, but the existed codes are using "nvidia-smi", whcih doesn't work on AMD GPU. so add the codes to check AMD Instinct GPU number

Test Plan

run the shell scripts of check_num_gpus on both AMD and NV platforms

Test Result

the check_num_gpus function could retrun the right number of AMD/NV GPUs

(Optional) Documentation Update

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[gemini-code-assist]

Code Review

This pull request adds support for detecting AMD Instinct GPUs to ensure the environment has at least two GPUs. The implementation has been updated to check for AMD GPUs by looking for a ROCm installation and using lspci. My feedback focuses on making this detection more robust by using the standard rocm-smi utility instead of relying on installation paths and parsing lspci output.

[gemini-code-assist]

The current method for detecting AMD GPUs has a few potential issues that could make it unreliable:

1. Dependency on /opt/rocm: It assumes ROCm is always installed in /opt/rocm. This might not be true for all installations or distributions.
2. Fragile lspci parsing: Relying on lspci | grep Instinct is brittle. The output format of lspci can change, and the string "Instinct" might not be present for all AMD data center GPUs, or it could accidentally match other devices.

A more robust approach is to use rocm-smi, which is the AMD equivalent of nvidia-smi. We can check for the availability of nvidia-smi or rocm-smi and then use the appropriate command to count GPUs. This avoids hardcoded paths and fragile text parsing.

Suggested change

	if [ ! -d "/opt/rocm" ]; then
	num_gpus=$(nvidia-smi --query-gpu=name --format=csv,noheader | wc -l)
	else
	num_gpus=$(lspci | grep Instinct | wc -l)
	fi
	if command -v nvidia-smi &> /dev/null; then
	num_gpus=$(nvidia-smi --query-gpu=name --format=csv,noheader | wc -l)
	elif command -v rocm-smi &> /dev/null; then
	# rocm-smi --showid lists the GPU IDs, one per line.
	num_gpus=$(rocm-smi --showid | wc -l)
	else
	echo "Error: Neither nvidia-smi nor rocm-smi found. Cannot determine GPU count."
	exit 1
	fi

[DarkLight1337]

LGTM, thanks