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authorSven Eckelmann2025-12-01 12:58:40 +0000
committerRobert Marko2025-12-02 09:42:24 +0000
commit141ac0b2bd1e7cbad1a75fe17a7b47a3778d16ca (patch)
treea327ec4c89e72d7ed045cee4fabbca48cacb78f0
parent2bc79783233c5d8612bfa5831cd334cab62b3e5e (diff)
downloadopenwrt-141ac0b2bd1e7cbad1a75fe17a7b47a3778d16ca.tar.gz
realtek: dsa: rtl930x: Fix flow control with ingress shaping
Tests with ingress shaping and enabled flow control showed really high packet loss. It seems like the MAC pause frames are not created correctly when both burst high off is set to the same value as burst high on. By default, RTL930x has set the burst high values to: * on: 64K * off: 32K Using the same 1:2 ratio seems to solve the high packet loss rate during UDP tests. Fixes: 2e74eb6d93a7 ("realtek: dsa: rtl93xx: Support per port throttling") Signed-off-by: Sven Eckelmann <se@simonwunderlich.de> Link: https://github.com/openwrt/openwrt/pull/21011 Signed-off-by: Robert Marko <robimarko@gmail.com>
-rw-r--r--target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl930x.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl930x.c b/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl930x.c
index fb25b9cf0b..bb41acaf64 100644
--- a/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl930x.c
+++ b/target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl930x.c
@@ -208,9 +208,13 @@ static int rtldsa_930x_port_rate_police_add(struct dsa_switch *ds, int port,
if (ingress) {
burst = min_t(u32, act->police.burst, RTL930X_BANDWIDTH_CTRL_INGRESS_BURST_MAX);
- /* set burst high on/off the same to avoid TCP oscillation */
+ /* the linux kernel only provides a single burst value. But the
+ * realtek HW needs two. And to get flow control correctly
+ * working, the realtek default ratio of 1:2 seems to work
+ * reasonable well
+ */
sw_w32(burst, RTL930X_BANDWIDTH_CTRL_INGRESS_BURST_HIGH_ON(port));
- sw_w32(burst, RTL930X_BANDWIDTH_CTRL_INGRESS_BURST_HIGH_OFF(port));
+ sw_w32(burst / 2, RTL930X_BANDWIDTH_CTRL_INGRESS_BURST_HIGH_OFF(port));
/* Enable ingress bandwidth flow control to improve TCP throughput and avoid
* the drops behavior of the RTL930x ingress rate limiter which seem to not