linux-kernel - [PATCH] staging: octeon-ethernet: disable load balance for receiving packet when CONFIG

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Date:	Thu, 30 Oct 2014 01:09:01 +0000 (GMT)
From:	Eunbong Song <eunb.song@...sung.com>
To:	"ralf@...ux-mips.org" <ralf@...ux-mips.org>, david.daney@...ium.com
Cc:	gregkh@...uxfoundation.org, linux-mips@...ux-mips.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] staging: octeon-ethernet: disable load balance for receiving
 packet when CONFIG_RPS is enabled.


It's better disable load balance for receiving packet when CONFIG_RPS is enabled.
If not, octeon-ethernet driver select CPU and then the rps select again CPU.
It can be ipi interrupts overhead and packet reordering could be possible.

Signed-off-by: Eunbong Song <eunb.song@...sung.com>
---
 drivers/staging/octeon/ethernet-rx.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/staging/octeon/ethernet-rx.c b/drivers/staging/octeon/ethernet-rx.c
index b2b6c3c..44e372f 100644
--- a/drivers/staging/octeon/ethernet-rx.c
+++ b/drivers/staging/octeon/ethernet-rx.c
@@ -286,6 +286,7 @@ static int cvm_oct_napi_poll(struct napi_struct *napi, int budget)
 			did_work_request = 1;
 		}
 
+#ifndef CONFIG_RPS
 		if (rx_count == 0) {
 			/*
 			 * First time through, see if there is enough
@@ -300,6 +301,7 @@ static int cvm_oct_napi_poll(struct napi_struct *napi, int budget)
 			if (backlog > budget * cores_in_use && napi != NULL)
 				cvm_oct_enable_one_cpu();
 		}
+#endif
 		rx_count++;
 
 		skb_in_hw = USE_SKBUFFS_IN_HW && work->word2.s.bufs == 1;
-- 
1.7.0.1