Thread (10 messages) 10 messages, 2 authors, 2024-11-11

Re: [PATCH net-next 1/2] net: ethernet: ti: am65-cpsw: update pri_thread_map as per IEEE802.1Q-2004

From: Roger Quadros <rogerq@kernel.org>
Date: 2024-11-06 08:51:15
Also in: linux-omap, lkml


On 06/11/2024 07:22, Siddharth Vadapalli wrote:
On Tue, Nov 05, 2024 at 04:18:10PM +0200, Roger Quadros wrote:

Hello Roger,
quoted
IEEE802.1Q-2004 superseeds IEEE802.1D-2004. Now Priority Code Point (PCP)
nitpick: s/superseeds/supersedes
ok
Also, according to:
https://standards.ieee.org/ieee/802.1D/3387/
IEEE 802.1D-2004 is superseded by 802.1Q-2014, so:
s/IEEE802.1Q-2004/IEEE802.1Q-2014/g
quoted
2 is no longer at a lower priority than PCP 0. PCP 1 (Background) is still
at a lower priority than PCP 0 (Best Effort).

Reference:
IEEE802.1Q-2004, Standard for Local and metropolitan area networks
  Table G-2 - Traffic type acronyms
  Table G-3 - Defining traffic types
In IEEE802.1Q-2014, the tables are:
Table I-2—Traffic type acronyms
Table I-3—Defining traffic types
Thanks!
quoted
Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/net/ethernet/ti/cpsw_ale.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ethernet/ti/cpsw_ale.c b/drivers/net/ethernet/ti/cpsw_ale.c
index 8d02d2b21429..7dadd95cadc5 100644
--- a/drivers/net/ethernet/ti/cpsw_ale.c
+++ b/drivers/net/ethernet/ti/cpsw_ale.c
@@ -1692,26 +1692,29 @@ static void cpsw_ale_policer_reset(struct cpsw_ale *ale)
 void cpsw_ale_classifier_setup_default(struct cpsw_ale *ale, int num_rx_ch)
 {
 	int pri, idx;
-	/* IEEE802.1D-2004, Standard for Local and metropolitan area networks
+	/* IEEE802.1Q-2004, Standard for Local and metropolitan area networks
 	 *    Table G-2 - Traffic type acronyms
 	 *    Table G-3 - Defining traffic types
-	 * User priority values 1 and 2 effectively communicate a lower
-	 * priority than 0. In the below table 0 is assigned to higher priority
-	 * thread than 1 and 2 wherever possible.
+	 * Also: https://en.wikipedia.org/wiki/IEEE_P802.1p#Priority_levels
Since links might change, it might be better to drop this and quote section
I.4 Traffic types and priority values of IEEE802.1Q-2014 which states:

"0 is thus used both for default priority and for Best Effort, and
Background is associated with a priority value of 1. This means that the
value 1 effectively communicates a lower priority than 0."
I agree. Will update in v2. Thanks for review.
quoted
+	 * Priority Code Point (PCP) value 1 (Background) communicates a lower
+	 * priority than 0 (Best Effort). In the below table PCP 0 is assigned
+	 * to a higher priority thread than PCP 1 wherever possible.
 	 * The below table maps which thread the user priority needs to be
 	 * sent to for a given number of threads (RX channels). Upper threads
 	 * have higher priority.
 	 * e.g. if number of threads is 8 then user priority 0 will map to
-	 * pri_thread_map[8-1][0] i.e. thread 2
+	 * pri_thread_map[8-1][0] i.e. thread 1
 	 */
-	int pri_thread_map[8][8] = {	{ 0, 0, 0, 0, 0, 0, 0, 0, },
+
+	int pri_thread_map[8][8] = {   /* BK,BE,EE,CA,VI,VO,IC,NC */
+					{ 0, 0, 0, 0, 0, 0, 0, 0, },
 					{ 0, 0, 0, 0, 1, 1, 1, 1, },
 					{ 0, 0, 0, 0, 1, 1, 2, 2, },
-					{ 1, 0, 0, 1, 2, 2, 3, 3, },
-					{ 1, 0, 0, 1, 2, 3, 4, 4, },
-					{ 1, 0, 0, 2, 3, 4, 5, 5, },
-					{ 1, 0, 0, 2, 3, 4, 5, 6, },
-					{ 2, 0, 1, 3, 4, 5, 6, 7, } };
+					{ 0, 0, 1, 1, 2, 2, 3, 3, },
+					{ 0, 0, 1, 1, 2, 2, 3, 4, },
+					{ 1, 0, 2, 2, 3, 3, 4, 5, },
+					{ 1, 0, 2, 3, 4, 4, 5, 6, },
+					{ 1, 0, 2, 3, 4, 5, 6, 7 } };
 
 	cpsw_ale_policer_reset(ale);
Regards,
Siddharth.
-- 
cheers,
-roger
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