Re: [lwip-users] Maximizing TCP throughput

[Norbert Morawski]

Maybe try window scaling?

On November 12, 2024 17:18:41 Meganathan Raja Mani <meganathanraja@gmail.com> wrote:

Hi

Integrated the lwIP stack over DPDK and the application is written by using the lwIP raw API(NO_SYS=1).

The main purpose of the application is to get max TCP throughput(10Gbps).

Application is in full receiving(server) mode, which just sends ACK for the client data.

The lwIP application and client app are cross connected with 10Gbps intel 82599 NIC card.

The application has three threads. Each thread is pinned to a separate core(Intel Xeon 3.1 GHz).

All the threads are running in a poll mode.

1. One thread receives the packets from DPDK and enqueues into rte ring.
2. Second thread takes the packets from rte ring and converts into pbuf and then passes it to lwIP stack by calling ip_input function. In the receive callback, the app just frees the pbuf(does nothing).
3. Third thread reads data from lwIP stack and sends out to DPDK

 

Changed following things in lwIP stack.

#define TCP_TMR_INTERVAL            5  /* The TCP timer interval in milliseconds. */

#define MEMP_NUM_PBUF               (10028)

#define MEMP_NUM_TCP_SEG            160

#define TCP_SND_QUEUELEN            MEMP_NUM_TCP_SEG

#define PBUF_POOL_SIZE              (10 * 1024)

#define TCP_MSS                     1460

#define TCP_WND                     65535

#define LWIP_CHECKSUM_ON_COPY       1

#define TCP_SND_BUF                 65535

#define TCP_SNDLOWAT                TCP_SND_BUF/2 

#define MEMP_NUM_TCPIP_MSG_INPKT    160

#define CHECKSUM_CHECK_IP           0

#define CHECKSUM_CHECK_TCP          0

#define LWIP_DEBUG                  0

#define LWIP_ICMP                   1

#define MEM_USE_POOLS               1

#define MEM_SIZE                    (128 * 1024 * 1024)

#define MEM_ALIGNMENT               4 

#define ETH_PAD_SIZE                2 

#define LWIP_CHKSUM_ALGORITHM       2

#define LWIP_TCP_KEEPALIVE          1   

Disable nagle(tcp_nagle_disable) for the pcb

The stats_display() function doesn’t show any errors.

With this,I can get max 2K packets per second(25 Mbps), which is very low.

Any info about the max throughput can we get it with lwIP TCP protocol on any platform?

Please let me know what I should do to get max throughput (line rate 10 Gbps).

 

Regards,

Meganathan

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