From: Kan Liang <kan.li...@intel.com>
Network devices usually have many queues. Each queue has its own
tx_usecs options. Currently, we can only set all the queues with same
value by ethtool. This patch expose the tx_usecs in sysfs. So the user
can set/get per queue coalesce parameter tx_usecs by sysfs.
Signed-off-by: Kan Liang <kan.li...@intel.com>
---
Documentation/networking/scaling.txt | 12 ++++++++++++
include/linux/netdevice.h | 8 ++++++++
net/core/net-sysfs.c | 38 ++++++++++++++++++++++++++++++++++++
3 files changed, 58 insertions(+)
diff --git a/Documentation/networking/scaling.txt
b/Documentation/networking/scaling.txt
index 59f4db2..636192d 100644
--- a/Documentation/networking/scaling.txt
+++ b/Documentation/networking/scaling.txt
@@ -431,6 +431,18 @@ a max-rate attribute is supported, by setting a Mbps value
to
A value of zero means disabled, and this is the default.
+Per Queue interrupt moderation:
+=============================
+
+The interrupt moderation mechanism, which implemented by HW, employs
+a series of timers to limit the number of interrupts it generates.
+TX queue absolute delay timer can be set to a microseconds value with
+
+/sys/class/net/<dev>/queues/tx-<n>/tx_usecs
+
+For the device which doesn't support per queue interrupt moderation,
+it shows "N/A".
+
Further Information
===================
RPS and RFS were introduced in kernel 2.6.35. XPS was incorporated into
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7d2d1d7..9db5c57 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1059,6 +1059,10 @@ typedef u16 (*select_queue_fallback_t)(struct net_device
*dev,
* This function is used to get egress tunnel information for given skb.
* This is useful for retrieving outer tunnel header parameters while
* sampling packet.
+ * void (*ndo_set_per_queue_tx_usecs)(struct net_device *dev,
+ * int index, u32 val);
+ * void (*ndo_get_per_queue_tx_usecs)(struct net_device *dev, int index);
+ * This function is used to set/get per queue coalesce parameter tx_usecs.
*
*/
struct net_device_ops {
@@ -1236,6 +1240,10 @@ struct net_device_ops {
bool proto_down);
int (*ndo_fill_metadata_dst)(struct net_device *dev,
struct sk_buff *skb);
+ void (*ndo_set_per_queue_tx_usecs)(struct net_device
*dev,
+ int index, u32
val);
+ u32 (*ndo_get_per_queue_tx_usecs)(struct net_device
*dev,
+ int index);
};
/**
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index f88a62a..48016b8 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1239,12 +1239,50 @@ static struct netdev_queue_attribute xps_cpus_attribute
=
__ATTR(xps_cpus, S_IRUGO | S_IWUSR, show_xps_map, store_xps_map);
#endif /* CONFIG_XPS */
+static ssize_t tx_usecs_show(struct netdev_queue *queue,
+ struct netdev_queue_attribute *attr,
+ char *buf)
+{
+ struct net_device *dev = queue->dev;
+ int index = queue - dev->_tx;
+ u32 val;
+
+ if (dev->netdev_ops->ndo_get_per_queue_tx_usecs) {
+ val = dev->netdev_ops->ndo_get_per_queue_tx_usecs(dev, index);
+ return sprintf(buf, "%u\n", val);
+ }
+
+ return sprintf(buf, "N/A\n");
+}
+
+static ssize_t tx_usecs_store(struct netdev_queue *queue,
+ struct netdev_queue_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct net_device *dev = queue->dev;
+ int index = queue - dev->_tx;
+ u32 val, ret;
+
+ ret = kstrtouint(buf, 0, &val);
+ if (ret < 0)
+ return -EINVAL;
+
+ if (dev->netdev_ops->ndo_set_per_queue_tx_usecs)
+ dev->netdev_ops->ndo_set_per_queue_tx_usecs(dev, index, val);
+
+ return len;
+}
+
+static struct netdev_queue_attribute tx_usecs_attribute =
+ __ATTR(tx_usecs, S_IRUGO | S_IWUSR, tx_usecs_show, tx_usecs_store);
+
static struct attribute *netdev_queue_default_attrs[] = {
&queue_trans_timeout.attr,
#ifdef CONFIG_XPS
&xps_cpus_attribute.attr,
&queue_tx_maxrate.attr,
#endif
+ &tx_usecs_attribute.attr,
NULL
};
--
1.7.11.7
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