Re: [E1000-devel] Transmission limit
From: Robert Olsson <hidden>
Date: 2004-12-02 18:23:24
Possibly related (same subject, not in this thread)
- 2004-11-27 · Re: [E1000-devel] Transmission limit · Harald Welte <laforge@gnumonks.org>
Hello! Below is little patch to clean skb at xmit. It's old jungle trick Jamal and I used w. tulip. Note we can now even decrease the size of TX ring. It can increase TX performance from 800 kpps to 1125128pps 576Mb/sec (576065536bps) errors: 0 1124946pps 575Mb/sec (575972352bps) errors: 0 But suffers from scheduling problems as the previous patch. Often we just get 582108pps 298Mb/sec (298039296bps) errors: 0 When the sender CPU free (it's) skb's. we might get some "TX free affinity" which are unrelated to irq affinity of course not 100% perfect. And some of Scotts may still be used.
--- drivers/net/e1000/e1000.h.orig 2004-12-01 13:59:36.000000000 +0100
+++ drivers/net/e1000/e1000.h 2004-12-02 20:11:31.000000000 +0100@@ -103,7 +103,7 @@ #define E1000_MAX_INTR 10 /* TX/RX descriptor defines */ -#define E1000_DEFAULT_TXD 256 +#define E1000_DEFAULT_TXD 128 #define E1000_MAX_TXD 256 #define E1000_MIN_TXD 80 #define E1000_MAX_82544_TXD 4096 --- drivers/net/e1000/e1000_main.c.orig 2004-12-01 13:59:36.000000000 +0100 +++ drivers/net/e1000/e1000_main.c 2004-12-02 20:37:40.000000000 +0100
@@ -1820,6 +1820,10 @@ return NETDEV_TX_LOCKED; } + + if( adapter->tx_ring.next_to_use - adapter->tx_ring.next_to_clean > 80 ) + e1000_clean_tx_ring(adapter); + /* need: count + 2 desc gap to keep tail from touching * head, otherwise try next time */ if(E1000_DESC_UNUSED(&adapter->tx_ring) < count + 2) {
--ro