netdev - [PATCH net-next] r8169: speed up rtl_loop

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Date:   Sat, 4 May 2019 15:20:38 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Realtek linux nic maintainers <nic_swsd@...ltek.com>,
        David Miller <davem@...emloft.net>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net-next] r8169: speed up rtl_loop_wait

When testing I figured out that most operations signal finish even
before we trigger the first delay. Seems like PCI(e) access and
memory barriers typically add enough latency. Therefore move the
first delay after the first check.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/net/ethernet/realtek/r8169.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 4f1b6e97f..8c41b74ce 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -775,9 +775,9 @@ static bool rtl_loop_wait(struct rtl8169_private *tp, const struct rtl_cond *c,
 	int i;
 
 	for (i = 0; i < n; i++) {
-		delay(d);
 		if (c->check(tp) == high)
 			return true;
+		delay(d);
 	}
 	netif_err(tp, drv, tp->dev, "%s == %d (loop: %d, delay: %d).\n",
 		  c->msg, !high, n, d);
-- 
2.21.0