[source] ag71xx: Reduce NAPI weight to 32.

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/1c2fdfbaf2fac968706a6fe8ac85af3ba4f27239

commit 1c2fdfbaf2fac968706a6fe8ac85af3ba4f27239
Author: Rosen Penev <rosenp at gmail.com>
AuthorDate: Mon Dec 4 11:40:22 2017 -0800

    ag71xx: Reduce NAPI weight to 32.
    
    Qualcomm claims this reduces cache misses. Original commit message below:
    
    From: Ben Menchaca <ben.menchaca at qca.qualcomm.com>
    Date: Tue, 11 Jun 2013 12:18:46 -0500
    Subject: [ag71xx] reduce NAPI weight
    
    In an attempt to increase our cache warmth, we are decreasing NAPI.
    This increases the warmth of the reused SKBs.
    
    Signed-off-by: Ben Menchaca <ben.menchaca at qca.qualcomm.com>
    Signed-off-by: Rosen Penev <rosenp at gmail.com>
---
 .../ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h      | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
index 898bde1..a712812 100644
--- a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
+++ b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
@@ -40,7 +40,12 @@
 #define AG71XX_DRV_NAME		"ag71xx"
 #define AG71XX_DRV_VERSION	"0.5.35"
 
-#define AG71XX_NAPI_WEIGHT	64
+/*
+ * For our NAPI weight bigger does *NOT* mean better - it means more
+ * D-cache misses and lots more wasted cycles than we'll ever
+ * possibly gain from saving instructions.
+ */
+#define AG71XX_NAPI_WEIGHT	32
 #define AG71XX_OOM_REFILL	(1 + HZ/10)
 
 #define AG71XX_INT_ERR	(AG71XX_INT_RX_BE | AG71XX_INT_TX_BE)