2018-08-15 20:31:07

by Ivan Khoronzhuk

Subject: [PATCH net-next] Documentation: networking: ti-cpsw: correct cbs parameters for Eth1 100Mb

If set cbs parameters calculated for 1000Mb, but use on 100Mb port
w/o h/w offload (for cpsw offload it doesn't matter), it works
incorrectly. According to the example and testing board, second port
is 100Mb interface. Correct them on recalculated for 100Mb interface.
It allows to use the same command for CBS software implementation for
board in example.

Signed-off-by: Ivan Khoronzhuk <[email protected]>
---
Based on net-next/master

Documentation/networking/ti-cpsw.txt | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/Documentation/networking/ti-cpsw.txt b/Documentation/networking/ti-cpsw.txt
index 67039205bd69..d4d4c0751a09 100644
--- a/Documentation/networking/ti-cpsw.txt
+++ b/Documentation/networking/ti-cpsw.txt
@@ -469,17 +469,18 @@ $ tc -g class show dev eth1

14)
// Set rate for class A - 31 Mbit (tc0, txq2) using CBS Qdisc for Eth1
-// here only idle slope is important, others ignored
+// here only idle slope is important, others ignored, but calculated
+// for interface speed - 100Mb for eth1 port.
// Set it +1 Mb for reserve (important!)
-$ tc qdisc add dev eth1 parent 100:3 cbs locredit -1453 \
-hicredit 47 sendslope -969000 idleslope 31000 offload 1
+$ tc qdisc add dev eth1 parent 100:3 cbs locredit -1035 \
+hicredit 465 sendslope -69000 idleslope 31000 offload 1
net eth1: set FIFO3 bw = 31

15)
// Set rate for class B - 11 Mbit (tc1, txq3) using CBS Qdisc for Eth1
// Set it +1 Mb for reserve (important!)
-$ tc qdisc add dev eth1 parent 100:4 cbs locredit -1483 \
-hicredit 34 sendslope -989000 idleslope 11000 offload 1
+$ tc qdisc add dev eth1 parent 100:4 cbs locredit -1335 \
+hicredit 405 sendslope -89000 idleslope 11000 offload 1
net eth1: set FIFO2 bw = 11

16)
--
2.17.1

2018-08-16 19:29:19

by David Miller

Subject: Re: [PATCH net-next] Documentation: networking: ti-cpsw: correct cbs parameters for Eth1 100Mb

From: Ivan Khoronzhuk <[email protected]>
Date: Wed, 15 Aug 2018 23:29:53 +0300

> If set cbs parameters calculated for 1000Mb, but use on 100Mb port
> w/o h/w offload (for cpsw offload it doesn't matter), it works
> incorrectly. According to the example and testing board, second port
> is 100Mb interface. Correct them on recalculated for 100Mb interface.
> It allows to use the same command for CBS software implementation for
> board in example.
>
> Signed-off-by: Ivan Khoronzhuk <[email protected]>

Applied, thanks.