sdkconfig: improve TCP performance

The default TCP window size is too low for anything but low-latency links. This causes stuttering audio for WIS TTS. Increase the default TCP window size to 16 * MSS (1440), and adapt the receive mailbox size according to the LwIP documentation. Similar issues could happen with WIS for STT, so let's increase the default TCP send buffer size also. Both the TCP send buffer and receive window size were 5740 before this change. While at it, also enable TCP SACK, which can improve overal performance by reducing unnecessary retransmissions.
toverainc · Dec 29, 2023 · 4dc60eb · 4dc60eb
1 parent f64b28c
commit 4dc60eb
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/sdkconfig.defaults b/sdkconfig.defaults
@@ -91,6 +91,10 @@ CONFIG_LWIP_DHCP_GET_NTP_SRV=y
 CONFIG_LWIP_DHCP_MAX_NTP_SERVERS=1
 CONFIG_LWIP_LOCAL_HOSTNAME="willow"
 CONFIG_LWIP_TCPIP_TASK_AFFINITY_CPU0=y
+CONFIG_LWIP_TCP_SND_BUF_DEFAULT=23040
+CONFIG_LWIP_TCP_WND_DEFAULT=23040
+CONFIG_LWIP_TCP_RECVMBOX_SIZE=18
+CONFIG_LWIP_TCP_SACK_OUT=y
 CONFIG_MBEDTLS_CERTIFICATE_BUNDLE_MAX_CERTS=1000
 CONFIG_MBEDTLS_EXTERNAL_MEM_ALLOC=y
 CONFIG_MBEDTLS_HARDWARE_AES=y