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authorJesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>2018-07-03 15:42:54 -0700
committerDavid S. Miller <davem@davemloft.net>2018-07-04 22:30:27 +0900
commit88cab77162e86e0f6a2b7e4f859c1435c4e24feb (patch)
treeb1d0a9eb918967fa9e8007a2b65a6ca8a746bc3b
parent25db26a91364db00f5a30da2fea8e9afe14a163c (diff)
net/sched: Add HW offloading capability to ETF
Add infra so etf qdisc supports HW offload of time-based transmission. For hw offload, the time sorted list is still used, so packets are dequeued always in order of txtime. Example: $ tc qdisc replace dev enp2s0 parent root handle 100 mqprio num_tc 3 \ map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@2 hw 0 $ tc qdisc add dev enp2s0 parent 100:1 etf offload delta 100000 \ clockid CLOCK_REALTIME In this example, the Qdisc will use HW offload for the control of the transmission time through the network adapter. The hrtimer used for packets scheduling inside the qdisc will use the clockid CLOCK_REALTIME as reference and packets leave the Qdisc "delta" (100000) nanoseconds before their transmission time. Because this will be using HW offload and since dynamic clocks are not supported by the hrtimer, the system clock and the PHC clock must be synchronized for this mode to behave as expected. Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/pkt_sched.h5
-rw-r--r--include/uapi/linux/pkt_sched.h1
-rw-r--r--net/sched/sch_etf.c71
3 files changed, 76 insertions, 1 deletions
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index 2466ea143d01..7dc769e5452b 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -155,4 +155,9 @@ struct tc_cbs_qopt_offload {
s32 sendslope;
};
+struct tc_etf_qopt_offload {
+ u8 enable;
+ s32 queue;
+};
+
#endif
diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h
index d5e933ce1447..949118461009 100644
--- a/include/uapi/linux/pkt_sched.h
+++ b/include/uapi/linux/pkt_sched.h
@@ -944,6 +944,7 @@ struct tc_etf_qopt {
__s32 clockid;
__u32 flags;
#define TC_ETF_DEADLINE_MODE_ON BIT(0)
+#define TC_ETF_OFFLOAD_ON BIT(1)
};
enum {
diff --git a/net/sched/sch_etf.c b/net/sched/sch_etf.c
index 4b7f4903ac17..932a136db568 100644
--- a/net/sched/sch_etf.c
+++ b/net/sched/sch_etf.c
@@ -20,8 +20,10 @@
#include <net/sock.h>
#define DEADLINE_MODE_IS_ON(x) ((x)->flags & TC_ETF_DEADLINE_MODE_ON)
+#define OFFLOAD_IS_ON(x) ((x)->flags & TC_ETF_OFFLOAD_ON)
struct etf_sched_data {
+ bool offload;
bool deadline_mode;
int clockid;
int queue;
@@ -45,6 +47,9 @@ static inline int validate_input_params(struct tc_etf_qopt *qopt,
* * Dynamic clockids are not supported.
*
* * Delta must be a positive integer.
+ *
+ * Also note that for the HW offload case, we must
+ * expect that system clocks have been synchronized to PHC.
*/
if (qopt->clockid < 0) {
NL_SET_ERR_MSG(extack, "Dynamic clockids are not supported");
@@ -225,6 +230,56 @@ out:
return skb;
}
+static void etf_disable_offload(struct net_device *dev,
+ struct etf_sched_data *q)
+{
+ struct tc_etf_qopt_offload etf = { };
+ const struct net_device_ops *ops;
+ int err;
+
+ if (!q->offload)
+ return;
+
+ ops = dev->netdev_ops;
+ if (!ops->ndo_setup_tc)
+ return;
+
+ etf.queue = q->queue;
+ etf.enable = 0;
+
+ err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_ETF, &etf);
+ if (err < 0)
+ pr_warn("Couldn't disable ETF offload for queue %d\n",
+ etf.queue);
+}
+
+static int etf_enable_offload(struct net_device *dev, struct etf_sched_data *q,
+ struct netlink_ext_ack *extack)
+{
+ const struct net_device_ops *ops = dev->netdev_ops;
+ struct tc_etf_qopt_offload etf = { };
+ int err;
+
+ if (q->offload)
+ return 0;
+
+ if (!ops->ndo_setup_tc) {
+ NL_SET_ERR_MSG(extack, "Specified device does not support ETF offload");
+ return -EOPNOTSUPP;
+ }
+
+ etf.queue = q->queue;
+ etf.enable = 1;
+
+ err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_ETF, &etf);
+ if (err < 0) {
+ NL_SET_ERR_MSG(extack, "Specified device failed to setup ETF hardware offload");
+ return err;
+ }
+
+ return 0;
+}
+
static int etf_init(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
@@ -251,8 +306,9 @@ static int etf_init(struct Qdisc *sch, struct nlattr *opt,
qopt = nla_data(tb[TCA_ETF_PARMS]);
- pr_debug("delta %d clockid %d deadline %s\n",
+ pr_debug("delta %d clockid %d offload %s deadline %s\n",
qopt->delta, qopt->clockid,
+ OFFLOAD_IS_ON(qopt) ? "on" : "off",
DEADLINE_MODE_IS_ON(qopt) ? "on" : "off");
err = validate_input_params(qopt, extack);
@@ -261,9 +317,16 @@ static int etf_init(struct Qdisc *sch, struct nlattr *opt,
q->queue = sch->dev_queue - netdev_get_tx_queue(dev, 0);
+ if (OFFLOAD_IS_ON(qopt)) {
+ err = etf_enable_offload(dev, q, extack);
+ if (err < 0)
+ return err;
+ }
+
/* Everything went OK, save the parameters used. */
q->delta = qopt->delta;
q->clockid = qopt->clockid;
+ q->offload = OFFLOAD_IS_ON(qopt);
q->deadline_mode = DEADLINE_MODE_IS_ON(qopt);
switch (q->clockid) {
@@ -326,10 +389,13 @@ static void etf_reset(struct Qdisc *sch)
static void etf_destroy(struct Qdisc *sch)
{
struct etf_sched_data *q = qdisc_priv(sch);
+ struct net_device *dev = qdisc_dev(sch);
/* Only cancel watchdog if it's been initialized. */
if (q->watchdog.qdisc == sch)
qdisc_watchdog_cancel(&q->watchdog);
+
+ etf_disable_offload(dev, q);
}
static int etf_dump(struct Qdisc *sch, struct sk_buff *skb)
@@ -344,6 +410,9 @@ static int etf_dump(struct Qdisc *sch, struct sk_buff *skb)
opt.delta = q->delta;
opt.clockid = q->clockid;
+ if (q->offload)
+ opt.flags |= TC_ETF_OFFLOAD_ON;
+
if (q->deadline_mode)
opt.flags |= TC_ETF_DEADLINE_MODE_ON;