openwrt/target/linux/ipq806x/patches-6.1/700-04-net-stmmac-increase-TX-coalesce-timer-to-5ms.patch
Christian Marangi cafa8804a4
ipq806x: add patch fixing regression from stmmac TX timer
Add patch fixing regression from stmmac TX timer.

Refer to the single patch for extensive details on the problem.

This should restore original performance before 4.19 kernel.

Fixes: #11676
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
2023-09-30 16:55:09 +02:00

38 lines
1.5 KiB
Diff

From 95281ab33fbaa1e974bceb20cfb0f5c92934f2b3 Mon Sep 17 00:00:00 2001
From: Christian Marangi <ansuelsmth@gmail.com>
Date: Mon, 18 Sep 2023 15:11:13 +0200
Subject: [PATCH 4/4] net: stmmac: increase TX coalesce timer to 5ms
Commit 8fce33317023 ("net: stmmac: Rework coalesce timer and fix
multi-queue races") decreased the TX coalesce timer from 40ms to 1ms.
This caused some performance regression on some target (regression was
reported at least on ipq806x) in the order of 600mbps dropping from
gigabit handling to only 200mbps.
The problem was identified in the TX timer getting armed too much time.
While this was fixed and improved in another commit, performance can be
improved even further by increasing the timer delay a bit moving from
1ms to 5ms.
The value is a good balance between battery saving by prevending too
much interrupt to be generated and permitting good performance for
internet oriented devices.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
drivers/net/ethernet/stmicro/stmmac/common.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -286,7 +286,7 @@ struct stmmac_safety_stats {
#define MIN_DMA_RIWT 0x10
#define DEF_DMA_RIWT 0xa0
/* Tx coalesce parameters */
-#define STMMAC_COAL_TX_TIMER 1000
+#define STMMAC_COAL_TX_TIMER 5000
#define STMMAC_MAX_COAL_TX_TICK 100000
#define STMMAC_TX_MAX_FRAMES 256
#define STMMAC_TX_FRAMES 25