.. title: Bộ đệm vòng NIC & Máy tính ái lực IRQ
.. sên: nic-ring-buffer-máy tính
.. ngày: 27-03-2026 12:00:00 UTC
.. tags: linux, nic, irq, rss, hiệu suất, kernel, máy tính, công cụ
.. thể loại: Máy tính
.. liên kết:
.. mô tả: Tính toán kích thước bộ đệm vòng ethtool được đề xuất, số lượng hàng đợi RSS và chiến lược ghim mối quan hệ CPU dựa trên tốc độ giao diện, số lượng CPU và hồ sơ lưu lượng truy cập.
.. loại: văn bản
<style>
.calc-container { max-width: 900px; margin: 20px auto; padding: 20px; }
.calc-header { margin-bottom: 30px; padding: 25px; background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); border-radius: 12px; box-shadow: 0 4px 6px rgba(0,0,0,0.1); color: white; }
.calc-header h2 { margin-top: 0; color: white; font-size: 28px; margin-bottom: 10px; }
.calc-header p  { margin: 10px 0; opacity: 0.95; font-size: 15px; }
.input-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 15px; margin-top: 20px; }
.input-group { display: flex; flex-direction: column; }
.input-group label { margin-bottom: 8px; font-weight: 600; color: rgba(255,255,255,0.95); font-size: 14px; }
.input-group input, .input-group select { padding: 14px; font-size: 14px; border: 2px solid rgba(255,255,255,0.3); border-radius: 6px; background: rgba(255,255,255,0.95); transition: all 0.3s ease; box-sizing: border-box; }
.input-group input:focus, .input-group select:focus { outline: none; border-color: #4CAF50; background: white; box-shadow: 0 0 0 3px rgba(76,175,80,0.1); }
.button-container { margin-top: 20px; display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; }
.calc-button { padding: 14px 35px; font-size: 16px; background: #4CAF50; color: white; border: none; border-radius: 6px; cursor: pointer; font-weight: bold; transition: all 0.3s ease; box-shadow: 0 2px 4px rgba(0,0,0,0.2); }
.calc-button:hover { background: #45a049; transform: translateY(-1px); box-shadow: 0 4px 8px rgba(0,0,0,0.3); }
.calc-button:active { background: #3d8b40; transform: translateY(0); }
.help-text { margin-top: 15px; font-size: 14px; color: rgba(255,255,255,0.9); background: rgba(0,0,0,0.1); padding: 10px 15px; border-radius: 4px; }
.result-section { background: white; border: 1px solid #e0e0e0; border-radius: 8px; margin-top: 20px; overflow: hidden; box-shadow: 0 2px 4px rgba(0,0,0,0.05); transition: all 0.3s ease; }
.result-section:hover { box-shadow: 0 4px 8px rgba(0,0,0,0.1); }
.section-header { background: linear-gradient(135deg, #4CAF50 0%, #45a049 100%); color: white; padding: 15px 20px; font-size: 18px; font-weight: bold; }
.section-content { padding: 20px; background: #fafafa; }
.result-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 15px; }
.data-row { display: flex; flex-direction: column; padding: 15px; background: white; border-radius: 6px; border-left: 4px solid #4CAF50; box-shadow: 0 1px 3px rgba(0,0,0,0.05); }
.data-label { font-weight: bold; color: #555; font-size: 13px; margin-bottom: 8px; text-transform: uppercase; letter-spacing: 0.5px; }
.data-value { color: #4CAF50; font-family: 'Courier New', monospace; font-size: 20px; font-weight: bold; }
.data-value.small { font-size: 14px; }
.info-box { margin-top: 15px; padding: 15px; background: #e3f2fd; color: #1565c0; border-radius: 8px; border-left: 4px solid #2196F3; font-size: 14px; line-height: 1.6; }
table { width: 100%; border-collapse: collapse; }
th { background: linear-gradient(135deg, #4CAF50 0%, #45a049 100%); color: white; padding: 10px; text-align: left; }
td { padding: 8px 10px; border-bottom: 1px solid #eee; font-size: 13px; }
tr:hover td { background: #f8fff8; }
@media (max-width: 768px) { .input-grid, .result-grid { grid-template-columns: 1fr; } .calc-header h2 { font-size: 22px; } .calc-container { padding: 10px; } }
/* Page-specific */
.cmd-block { background: #1e1e2e; color: #cdd6f4; padding: 10px 14px; border-radius: 6px; font-family: 'Courier New', monospace; font-size: 12px; overflow-x: auto; white-space: pre; margin: 8px 0; }
.metric-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 15px; }
.metric-card { display: flex; flex-direction: column; padding: 15px; background: white; border-radius: 6px; border-left: 4px solid #4CAF50; box-shadow: 0 1px 3px rgba(0,0,0,0.05); }
.metric-label { font-weight: bold; color: #555; font-size: 13px; margin-bottom: 6px; text-transform: uppercase; }
.metric-value { color: #4CAF50; font-family: 'Courier New', monospace; font-size: 18px; font-weight: bold; }
.result-highlight { color: #4CAF50; font-weight: bold; font-size: 1.2em; }
</style>
<div class="calc-container">
<div class="calc-header">
<h2>Bộ đệm vòng NIC &amp; Máy tính ái lực IRQ</h2>
<p>Tính toán<code style="color:rgba(255,255,255,0.9);background:rgba(0,0,0,0.2);padding:2px 6px;border-radius:3px">ethtool -G</code>kích thước bộ đệm vòng, số lượng hàng đợi RSS và chiến lược ghim mối quan hệ/mất cân bằng CPU.</p>
<div class="input-grid">
<div class="input-group">
<label>Tốc độ giao diện</label>
<select id="linkSpeed">
<option value="1">1 Gbps</option>
<option selected="" value="10">10Gbps</option>
<option value="25">25 Gbps</option>
<option value="40">40Gbps</option>
<option value="100">100Gbps</option>
</select>
</div>
<div class="input-group">
<label>Lõi CPU có sẵn</label>
<input id="cpuCount" max="256" min="1" type="number" value="8"/>
</div>
<div class="input-group">
<label>Hồ sơ giao thông</label>
<select id="trafficProfile">
<option value="bulk">Hàng loạt / phát trực tuyến (khung lớn)</option>
<option selected="" value="rpc">Hỗn hợp / RPC (kích thước khung hình đa dạng)</option>
<option value="pps">PPS cao (khung nhỏ)</option>
</select>
</div>
<div class="input-group">
<label>Ngắt mục tiêu liên kết (μs)</label>
<input id="coalesceUs" max="1000" min="1" type="number" value="50"/>
</div>
<div class="input-group">
<label>Tên giao diện</label>
<input id="ifName" placeholder="eth0" type="text" value="eth0"/>
</div>
</div>
<div class="button-container">
<button class="calc-button" onclick="calcNic()">Tính toán</button>
</div>
</div>
<div id="nicResult" style="display:none"></div>
<div class="result-section">
<div class="section-header">Sự đánh đổi giữa bộ đệm vòng và tỷ lệ rớt</div>
<div class="section-content">
<table>
<tr><th>Kích thước vòng</th><th>Tác động độ trễ</th><th>Giảm rủi ro</th><th>Trường hợp sử dụng</th></tr>
<tr><td>256</td><td>Rất thấp</td><td>Cao (giọt nổ)</td><td>Ưu tiên thời gian thực, độ trễ thấp</td></tr>
<tr><td>512</td><td>Thấp</td><td>Trung bình</td><td>RPC nhạy cảm với độ trễ</td></tr>
<tr><td>1024</td><td>Trung bình</td><td>Thấp</td><td>Mục đích chung</td></tr>
<tr><td>2048</td><td>Trung bình-cao</td><td>Rất thấp</td><td>Truyền số lượng lớn, 10Gbps+</td></tr>
<tr><td>4096</td><td>Cao (thêm độ trễ)</td><td>Tối thiểu</td><td>100Gbps, PPS bền vững</td></tr>
</table>
</div>
</div>
</div>
<script>
function calcNic() {
    const speedGbps = parseInt(document.getElementById('linkSpeed').value);
    const cpus = parseInt(document.getElementById('cpuCount').value);
    const profile = document.getElementById('trafficProfile').value;
    const coalesceUs = parseInt(document.getElementById('coalesceUs').value);
    const iface = document.getElementById('ifName').value.trim() || 'eth0';
    const div = document.getElementById('nicResult');
    div.style.display = 'block';

    if (isNaN(cpus) || cpus < 1 || isNaN(coalesceUs) || coalesceUs < 1) {
        div.innerHTML = '<div class="result-section"><div class="section-header">Results</div><div class="section-content"><strong style="color:red">Invalid input.</strong></div></div>';
        return;
    }

    // Ring buffer sizing: ceil(link_speed_bps * coalesce_delay_s / (8 * frame_size))
    // Frame size heuristic by profile
    const frameSizes = { bulk: 9000, rpc: 1500, pps: 64 };
    const frameSize = frameSizes[profile];
    const speedBps = speedGbps * 1e9;
    const coalesceS = coalesceUs / 1e6;
    const rawRing = Math.ceil((speedBps * coalesceS) / (8 * frameSize));
    // Round up to nearest power of 2 (common NIC constraint)
    let ringSize = 1;
    while (ringSize < rawRing) ringSize *= 2;
    ringSize = Math.min(ringSize, 4096); // max typical ring size

    // RSS queues: min(cpus, speed-based cap, 64)
    const speedQueues = speedGbps <= 1 ? 4 : speedGbps <= 10 ? 8 : speedGbps <= 25 ? 16 : 32;
    const rssQueues = Math.min(cpus, speedQueues, 64);

    // CPU affinity: prefer first N CPUs, skip CPU 0 if NUMA/irqbalance concern
    const affinityCpus = rssQueues <= 4 ? `1-${rssQueues}` : `0-${rssQueues - 1}`;

    div.innerHTML = `<div class="result-section">
        <div class="section-header">Recommended Settings</div>
        <div class="section-content">
            <div class="metric-grid">
                <div class="metric-card"><div class="metric-value">${ringSize}</div><div class="metric-label">Ring buffer size (RX &amp; TX)</div></div>
                <div class="metric-card"><div class="metric-value">${rssQueues}</div><div class="metric-label">RSS queues</div></div>
                <div class="metric-card"><div class="metric-value">${coalesceUs} μs</div><div class="metric-label">Interrupt coalescing</div></div>
                <div class="metric-card"><div class="metric-value">${speedGbps} Gbps</div><div class="metric-label">Link speed</div></div>
            </div>
            <div class="info-box">
                <strong>Calculation:</strong> ceil(${speedGbps}Gbps &times; ${coalesceUs}μs / (8 &times; ${frameSize}B)) = ${rawRing} &rarr; rounded up to ${ringSize} (power of 2)
            </div>
            <div class="cmd-block"># Set ring buffer (${iface})
ethtool -G ${iface} rx ${ringSize} tx ${ringSize}

# Set RSS queue count
ethtool -L ${iface} combined ${rssQueues}

# Set interrupt coalescing
ethtool -C ${iface} rx-usecs ${coalesceUs} tx-usecs ${coalesceUs}

# Pin IRQs to CPUs ${affinityCpus} (run after ethtool -L)
# Find IRQ numbers: grep ${iface} /proc/interrupts | awk '{print $1}' | tr -d ':'
# Then: echo ${affinityCpus} > /proc/irq/&lt;N&gt;/smp_affinity_list

# Or use irqbalance with policy hint:
IRQBALANCE_ARGS="--policyscript=/etc/irqbalance/policy.sh" systemctl restart irqbalance</div>
            <button class="calc-button" style="margin-top:10px;padding:10px 24px;font-size:14px" onclick="copyBlock()">Copy Commands</button>
        </div>
    </div>`;

    window._lastCmds = `# Set ring buffer (${iface})\nethtool -G ${iface} rx ${ringSize} tx ${ringSize}\n\n# Set RSS queue count\nethtool -L ${iface} combined ${rssQueues}\n\n# Set interrupt coalescing\nethtool -C ${iface} rx-usecs ${coalesceUs} tx-usecs ${coalesceUs}`;
}

function copyBlock() {
    if (!window._lastCmds) return;
    navigator.clipboard.writeText(window._lastCmds).catch(() => {
        const ta = document.createElement('textarea');
        ta.value = window._lastCmds; document.body.appendChild(ta); ta.select(); document.execCommand('copy'); ta.remove();
    });
}
</script>