Show performance information about PCie for Mellanox adapters https://community.mellanox.com/s/article/understanding-pcie-configuration-for-maximum-performance

mlnx_pcie.sh

#!/usr/bin/env bash

_calc() { awk "BEGIN{print $*}"; }

_call_lspci() {
    local pcie="$1"

    lspci -s "$pcie" -vvv
}

get_cap_width() {
    _call_lspci "$1" | grep -oP "LnkCap.*Width x\K\d+"
}

get_sta_width() {
    _call_lspci "$1" | grep -oP "LnkSta.*Width x\K\d+"
}

get_cap_speed() {
    _call_lspci "$1" | grep -oP "LnkCap.*Speed \K\d+"
}

get_sta_speed() {
    _call_lspci "$1" | grep -oP "LnkSta.*Speed \K\d+"
}

get_cap_max_payload() {
    _call_lspci "$1" | grep -A 2 DevCap: | grep -oP "MaxPayload \K\d+"
}

get_ctl_max_payload() {
    _call_lspci "$1" | grep -A 2 DevCtl: | grep -oP "MaxPayload \K\d+"
}

get_ctl_max_read_request() {
    _call_lspci "$1" | grep -A 2 DevCtl: | grep -oP "MaxReadReq \K\d+"
}

get_pcie_gen() {
    _call_lspci "$1" | grep -oP "PCIeGen\K\d+"
}

get_encoding() {
    local pcie_gen="$1"

    if [[ $pcie_gen == 1 ]]; then
	echo "1/5";
    elif [[ $pcie_gen == 2 ]]; then
	echo "1/5";
    elif [[ $pcie_gen == 3 ]]; then
	echo "2/130";
    else
        echo "Unknown PCIe Gen: $pcie_gen" >&2
        exit 1;
    fi
}

for pcie in $(lspci | grep Mellanox | awk '{ print $1; }'); do
    echo "For the PCIe port:"
    lspci -s $pcie

    cap_width=$(get_cap_width "$pcie")
    cap_speed=$(get_cap_speed "$pcie")

    sta_width=$(get_sta_width "$pcie")
    sta_speed=$(get_sta_speed "$pcie")

    pcie_gen=$(get_pcie_gen "$pcie")
    encoding=$(get_encoding "$pcie_gen")

    cap_max_payload=$(get_cap_max_payload "$pcie")

    ctl_max_payload=$(get_ctl_max_payload "$pcie")
    ctl_max_read_request=$(get_ctl_max_read_request "$pcie")

    # Taken from Mellanox page
    current_speed=$(_calc "$sta_speed * $sta_width * (1 - $encoding) - 1")
    max_speed=$(_calc "$cap_speed * $cap_width * (1 - $encoding) - 1")

    echo "PCIe generation: $pcie_gen"
    echo "Encoding loss: $encoding"
    echo "Max Width: x$cap_width (current: x$sta_width)"
    echo "Max Speed: $cap_speed GT/s (current: $sta_speed GT/s)"
    echo "Max Payload: $cap_max_payload bytes (current: $ctl_max_payload bytes)"
    echo "Max Read Request: $ctl_max_read_request bytes"
    echo "Max PCIe Bandwidth: $max_speed Gb/s (current: $current_speed Gb/s)"

    echo
done