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Merged
SiskaPavel merged 4 commits into from
Feb 4, 2026
Merged

dpdk: move RSS configuration into port configuration #319

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c0c73b2
dpdk: move RSS configuration into port configuration
Dec 16, 2025
1f9217e
dpdk: add rss argument to set user specific rss offload
Feb 4, 2026
50391b4
ipfixprobed: add rss_offload option to DPDK input
Feb 4, 2026
5d7e650
dpdk: update README
Feb 4, 2026
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3 changes: 3 additions & 0 deletions init/config2args.py
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Original file line number Diff line number Diff line change
Expand Up @@ -157,6 +157,9 @@ def process_input_dpdk_plugin(settings):
mtu = settings.get("mtu", 1518)
if mtu is not None:
primary_param += f"mtu={mtu};"
rss_offload = settings.get("rss_offload", None)
if rss_offload is not None:
primary_param += f"rss={rss_offload};"
primary_param += f"eal={eal}\""

params = []
Expand Down
5 changes: 5 additions & 0 deletions init/link0.conf.example
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Expand Up @@ -35,6 +35,11 @@ input_plugin:
eal_opts: null # EAL options (null = default options)
mtu: null # Maximum Transmission Unit (defaults to RTE_ETHER_MAX_LEN)

# Our default RSS configuration is RTE_ETH_RSS_IP.
# Intel X710 (i40e) does not work reliably with it, so by default we use RSS provided by the NIC/driver.
# Set this explicitly to override the driver RSS configuration.
rss_offload: null

# Storage configuration (storage)
storage:
cache:
Expand Down
10 changes: 8 additions & 2 deletions init/schema.json
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Expand Up @@ -93,11 +93,11 @@
"ndp": {
"type": "object",
"properties": {
"device": {
"device": {
"type": "array",
"items": {
"type": "string"
}
}
},
"queues": {
"type": "string"
Expand Down Expand Up @@ -182,6 +182,12 @@
"string",
"null"
]
},
"rss_offload": {
"type": [
"integer",
"null"
]
}
},
"required": [
Expand Down
9 changes: 7 additions & 2 deletions src/plugins/input/dpdk/README.md
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Expand Up @@ -17,6 +17,7 @@ input_plugin:
workers_cpu_list: []
eal_opts: null
mtu: 1518
rss_offload: null
```

## Parameters
Expand All @@ -36,6 +37,7 @@ input_plugin:
|__workers_cpu_list__| [] (autofill) | List of CPU cores assigned to RX queues (must match number of rx_queues) |
|__eal_opts__ | null | Extra options to be passed to the DPDK EAL (Environment Abstraction Layer). Can be used for fine-tuning DPDK behavior.|
|__mtu__ | 1518 | Maximum Transmission Unit size for the interface. Defines the maximum packet size that can be received.|
|__rss_offload__ | null | RSS offload configuration. Can be used to override the default RSS offload configuration.|

## How to use

Expand Down Expand Up @@ -240,9 +242,12 @@ grubby --update-kernel ALL --args "isolcpus=2-19,22-39"
```


### 4. Validate with dpdk-testpmd
### 4. Troubleshooting

TODO
⚠️ RSS on Intel X710 (i40e)

We observed that RSS on Intel X710 (i40e) may not distribute packets across multiple RX queues with the default RTE_ETH_RSS_IP.
For X710 (i40e) we use full RSS offload provided by the driver. If you experience similar issues, try to set `rss_offload` explicitly to override the default RSS offload configuration.

## FAQ

Expand Down
4 changes: 3 additions & 1 deletion src/plugins/input/dpdk/src/dpdk.cpp
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Expand Up @@ -86,12 +86,14 @@ void DpdkCore::configure(const char* params)
uint16_t rxQueueCount = parser.rx_queues();
m_mBufsCount = parser.pkt_buffer_size();
uint16_t mtuSize = parser.mtu_size();
uint64_t rssOffload = parser.rss_offload();

configureEal(parser.eal_params());

m_dpdkDevices.reserve(parser.port_numbers().size());
for (auto portID : parser.port_numbers()) {
m_dpdkDevices.emplace_back(portID, rxQueueCount, mempoolSize, m_mBufsCount, mtuSize);
m_dpdkDevices
.emplace_back(portID, rxQueueCount, mempoolSize, m_mBufsCount, mtuSize, rssOffload);
}

isConfigured = true;
Expand Down
17 changes: 17 additions & 0 deletions src/plugins/input/dpdk/src/dpdk.hpp
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Expand Up @@ -34,6 +34,7 @@ class DpdkOptParser : public OptionsParser {
uint16_t rx_queues_ = 1;
std::string eal_;
uint16_t mtu_;
uint64_t rss_offload_ = 0;

std::vector<uint16_t> parsePortNumbers(std::string arg)
{
Expand Down Expand Up @@ -123,6 +124,20 @@ class DpdkOptParser : public OptionsParser {
return true;
},
RequiredArgument);
register_option(
"r",
"rss",
"VALUE",
"RSS offload value. Default: 0",
[this](const char* arg) {
try {
rss_offload_ = str2num<decltype(rss_offload_)>(arg);
} catch (std::invalid_argument&) {
return false;
}
return true;
},
RequiredArgument);
register_option(
"e",
"eal",
Expand Down Expand Up @@ -160,6 +175,8 @@ class DpdkOptParser : public OptionsParser {
uint16_t rx_queues() const { return rx_queues_; }

uint16_t mtu_size() const { return mtu_; }

uint64_t rss_offload() const { return rss_offload_; }
};

class DpdkCore {
Expand Down
57 changes: 35 additions & 22 deletions src/plugins/input/dpdk/src/dpdkDevice.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -42,7 +42,8 @@ DpdkDevice::DpdkDevice(
uint16_t rxQueueCount,
uint16_t memPoolSize,
uint16_t mbufsCount,
uint16_t mtuSize)
uint16_t mtuSize,
uint64_t rssOffload)
: m_portID(portID)
, m_rxQueueCount(rxQueueCount)
, m_txQueueCount(0)
Expand All @@ -51,13 +52,13 @@ DpdkDevice::DpdkDevice(
, m_supportedRSS(false)
, m_supportedHWTimestamp(false)
, m_mtuSize(mtuSize)
, m_rssOffload(rssOffload)
{
validatePort();
recognizeDriver();
configurePort();
initMemPools(memPoolSize);
setupRxQueues(memPoolSize);
configureRSS();
enablePort();
}

Expand Down Expand Up @@ -95,9 +96,13 @@ void DpdkDevice::recognizeDriver()
std::cerr << "\tflow type RSS offloads: " << rteDevInfo.flow_type_rss_offloads << std::endl;

/* Check if RSS hashing is supported in NIC */
m_supportedRSS = (rteDevInfo.flow_type_rss_offloads & RTE_ETH_RSS_IP) != 0;
std::cerr << "\tDetected RSS offload capability: " << (m_supportedRSS ? "yes" : "no")
<< std::endl;
if (m_rxQueueCount > 1) {
m_supportedRSS = (rteDevInfo.flow_type_rss_offloads & RTE_ETH_RSS_IP) != 0;
std::cerr << "\tDetected RSS offload capability: " << (m_supportedRSS ? "yes" : "no")
<< std::endl;
} else {
m_supportedRSS = false;
}

/* Check if HW timestamps are supported, we support NFB cards only */
if (m_isNfbDpdkDriver) {
Expand Down Expand Up @@ -154,7 +159,9 @@ rte_eth_conf DpdkDevice::createPortConfig()

if (m_supportedRSS) {
portConfig.rxmode.mq_mode = RTE_ETH_MQ_RX_RSS;
portConfig.rx_adv_conf.rss_conf = createRSSConfig();
} else {
std::cerr << "Skipped RSS hash setting for port " << m_portID << "." << std::endl;
portConfig.rxmode.mq_mode = RTE_ETH_MQ_RX_NONE;
}

Expand Down Expand Up @@ -220,12 +227,9 @@ void DpdkDevice::setupRxQueues(uint16_t memPoolSize)
<< " set up. Size of each queue: " << rxQueueSize << std::endl;
}

void DpdkDevice::configureRSS()
rte_eth_rss_conf DpdkDevice::createRSSConfig()
{
if (!m_supportedRSS) {
std::cerr << "Skipped RSS hash setting for port " << m_portID << "." << std::endl;
return;
}
struct rte_eth_rss_conf rssConfig = {};

rte_eth_dev_info rteDevInfo;
if (rte_eth_dev_info_get(m_portID, &rteDevInfo)) {
Expand All @@ -243,23 +247,32 @@ void DpdkDevice::configureRSS()
return hashKey[idx++ % sizeof(hashKey)];
});

const uint64_t rssOffloads = rteDevInfo.flow_type_rss_offloads & RTE_ETH_RSS_IP;
if (rssOffloads != RTE_ETH_RSS_IP) {
std::cerr << "RTE_ETH_RSS_IP is not supported by the card. Used subset: " << rssOffloads
<< std::endl;
uint64_t rssOffloads = 0;
if (m_rssOffload) { // user specified RSS offload
rssOffloads = m_rssOffload;
} else {
if (std::string(rteDevInfo.driver_name) == "net_i40e") {
std::cerr << "RTE_ETH_RSS_IP is not supported reliably by this driver, falling back to "
"NIC-provided RSS: "
<< rteDevInfo.flow_type_rss_offloads << std::endl;
std::cerr << "You can override this behavior using the 'rss' configuration parameter."
<< std::endl;
rssOffloads = rteDevInfo.flow_type_rss_offloads;
} else {
rssOffloads = rteDevInfo.flow_type_rss_offloads & RTE_ETH_RSS_IP;
if (rssOffloads != RTE_ETH_RSS_IP) {
std::cerr << "RTE_ETH_RSS_IP is not supported by the card. Used subset: "
<< rssOffloads << std::endl;
}
}
}

struct rte_eth_rss_conf rssConfig = {};
std::cerr << "Using RSS offloads: " << rssOffloads << std::endl;

rssConfig.rss_key = m_hashKey.data();
rssConfig.rss_key_len = rssHashKeySize;
rssConfig.rss_hf = rssOffloads;

int ret = rte_eth_dev_rss_hash_update(m_portID, &rssConfig);
if (ret < 0) {
std::cerr << "Setting RSS {" << rssOffloads << "} for port " << m_portID
<< " failed. Errno:" << ret << std::endl;
throw PluginError("DpdkDevice::configureRSS() has failed.");
}
return rssConfig;
}

void DpdkDevice::enablePort()
Expand Down
7 changes: 5 additions & 2 deletions src/plugins/input/dpdk/src/dpdkDevice.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -48,13 +48,15 @@ class DpdkDevice {
* @param memPoolSize The size of the memory pool for packet buffers.
* @param mbufsCount The number of mbufs (packet buffers) to be allocated.
* @param mtuSize Maximum transmission unit of input interface.
* @param rssOffload RSS offload value. 0 for subset of RTE_ETH_RSS_IP.
*/
DpdkDevice(
uint16_t portID,
uint16_t rxQueueCount,
uint16_t memPoolSize,
uint16_t mbufsCount,
uint16_t mtuSize);
uint16_t mtuSize,
uint64_t rssOffload);

/**
* @brief Receives packets from the specified receive queue of the DPDK device.
Expand Down Expand Up @@ -84,7 +86,7 @@ class DpdkDevice {
rte_eth_conf createPortConfig();
void initMemPools(uint16_t memPoolSize);
void setupRxQueues(uint16_t memPoolSize);
void configureRSS();
rte_eth_rss_conf createRSSConfig();
void enablePort();
void createRteMempool(uint16_t mempoolSize);
void setRxTimestampDynflag();
Expand All @@ -102,6 +104,7 @@ class DpdkDevice {
int m_rxTimestampOffset;
int m_rxTimestampDynflag;
uint16_t m_mtuSize;
uint64_t m_rssOffload = 0;
};

} // namespace ipxp