xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

gianfar: Change default HW Tx queue scheduling mode

Browse Source 
This is primarily to address transmission timeout occurrences, when
multiple H/W Tx queues are being used concurrently. Because in
the priority scheduling mode the controller does not service the
Tx queues equally (but in ascending index order), Tx timeouts are
being triggered rightaway for a basic test with multiple simultaneous
connections like:
iperf -c <server_ip> -n 100M -P 8

resulting in kernel trace:
NETDEV WATCHDOG: eth1 (fsl-gianfar): transmit queue <X> timed out
------------[ cut here ]------------
WARNING: at net/sched/sch_generic.c:255
...
and controller reset during intense traffic, and possibly further
complications.

This patch changes the default H/W Tx scheduling setting (TXSCHED)
for multi-queue devices, from priority scheduling mode to a weighted
round robin mode with equal weights for all H/W Tx queues, and
addresses the issue above.

Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Claudiu Manoil
2012-09-23 22:39:08 +00:00
committed by David S. Miller
parent 0cf833aefa
commit b98b8babd6
2 changed files with 20 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
drivers/net/ethernet/freescale/gianfar.c
View File

@@ -394,7 +394,13 @@ static void gfar_init_mac(struct net_device *ndev)
if (ndev->features & NETIF_F_IP_CSUM)
tctrl |= TCTRL_INIT_CSUM;
tctrl |= TCTRL_TXSCHED_PRIO;
if (priv->prio_sched_en)
tctrl |= TCTRL_TXSCHED_PRIO;
else {
tctrl |= TCTRL_TXSCHED_WRRS;
gfar_write(&regs->tr03wt, DEFAULT_WRRS_WEIGHT);
gfar_write(&regs->tr47wt, DEFAULT_WRRS_WEIGHT);
}
gfar_write(&regs->tctrl, tctrl);
@@ -1160,6 +1166,9 @@ static int gfar_probe(struct platform_device *ofdev)
priv->rx_filer_enable = 1;
/* Enable most messages by default */
priv->msg_enable = (NETIF_MSG_IFUP << 1 ) - 1;
/* use pritority h/w tx queue scheduling for single queue devices */
if (priv->num_tx_queues == 1)
priv->prio_sched_en = 1;
/* Carrier starts down, phylib will bring it up */
netif_carrier_off(dev);