[RFC PATCH 15/30] i40e/netpolicy: add MIX policy support

kan.liang
2016-07-18T14:31:47Z

Enable i40e MIX policy support. Based on the test, the MIX policy has
better performance if increasing rx interrupt moderation a little bit.

For evaluating the MIX policy performance, mixed workloads are tested.
The mixed workloads are combination of throughput-first workload and
latency-first workload. Five different types of combinations are
evaluated.
(pure throughput-first workload, pure latency-first workloads,
2/3 throughput-first workload + 1/3 latency-first workloads,
1/3 throughput-first workload + 2/3 latency-first workloads and
1/2 throughput-first workload + 1/2 latency-first workloads).

For caculating the performance of mixed workloads, a weighted sum system
is also introduced. Here is the formula.

Score = normalized_latency * Weight + normalized_throughput * (1 -
Weight).

If we assume that the user has an equal interest in latency and
throughput performance, the Score for "MIX" policy is on average ~1.52X
than baseline.

Signed-off-by: Kan Liang <kan.liang@intel.com>
---
drivers/net/ethernet/intel/i40e/i40e_main.c | 71 +++++++++++++++++++++--------
1 file changed, 51 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 11b921b..d3f087d 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -8966,6 +8966,8 @@ static netdev_features_t i40e_features_check(struct sk_buff *skb,
#define NET_POLICY_CPU_TX 250
#define NET_POLICY_BULK_RX 50
#define NET_POLICY_BULK_TX 125
+#define NET_POLICY_MIX_BULK_RX 62
+#define NET_POLICY_MIX_BULK_TX 122
#define NET_POLICY_LATENCY_RX 5
#define NET_POLICY_LATENCY_TX 10

@@ -9004,6 +9006,9 @@ static int i40e_ndo_netpolicy_init(struct net_device *dev,
set_bit(i, info->avail_policy);
}

+ /* support MIX policy */
+ info->has_mix_policy = true;
+
return 0;
}

@@ -9046,6 +9051,30 @@ static int i40e_ndo_get_irq_info(struct net_device *dev,
return 0;
}

+static int i40e_fill_coalesce_for_policy(struct ethtool_coalesce *ec,
+ enum netpolicy_name name)
+{
+ if (policy_param[name][NETPOLICY_RX] > 0) {
+ ec->rx_coalesce_usecs = policy_param[name][NETPOLICY_RX];
+ ec->use_adaptive_rx_coalesce = 0;
+ } else if (policy_param[name][NETPOLICY_RX] == 0) {
+ ec->use_adaptive_rx_coalesce = 1;
+ } else {
+ return -EINVAL;
+ }
+
+ if (policy_param[name][NETPOLICY_TX] > 0) {
+ ec->tx_coalesce_usecs = policy_param[name][NETPOLICY_TX];
+ ec->use_adaptive_tx_coalesce = 0;
+ } else if (policy_param[name][NETPOLICY_TX] == 0) {
+ ec->use_adaptive_tx_coalesce = 1;
+ } else {
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
/**
* i40e_set_net_policy
* @dev: the net device pointer
@@ -9061,28 +9090,30 @@ static int i40e_set_net_policy(struct net_device *dev,
struct i40e_vsi *vsi = np->vsi;
struct netpolicy_object *obj;
struct ethtool_coalesce ec;
-
- if (policy_param[name][NETPOLICY_RX] > 0) {
- ec.rx_coalesce_usecs = policy_param[name][NETPOLICY_RX];
- ec.use_adaptive_rx_coalesce = 0;
- } else if (policy_param[name][NETPOLICY_RX] == 0) {
- ec.use_adaptive_rx_coalesce = 1;
- } else {
- return -EINVAL;
- }
-
- if (policy_param[name][NETPOLICY_TX] > 0) {
- ec.tx_coalesce_usecs = policy_param[name][NETPOLICY_TX];
- ec.use_adaptive_tx_coalesce = 0;
- } else if (policy_param[name][NETPOLICY_TX] == 0) {
- ec.use_adaptive_tx_coalesce = 1;
- } else {
- return -EINVAL;
- }
+ int i, ret;

/*For i40e driver, tx and rx are always in pair */
- list_for_each_entry(obj, &dev->netpolicy->obj_list[NETPOLICY_RX][name], list) {
- i40e_set_itr_per_queue(vsi, &ec, obj->queue);
+ if (name == NET_POLICY_MIX) {
+ /* Under MIX policy, the paramers for BULK object are different */
+ policy_param[NET_POLICY_BULK][NETPOLICY_RX] = NET_POLICY_MIX_BULK_RX;
+ policy_param[NET_POLICY_BULK][NETPOLICY_TX] = NET_POLICY_MIX_BULK_TX;
+ for (i = NET_POLICY_NONE; i < NET_POLICY_MAX; i++) {
+ ret = i40e_fill_coalesce_for_policy(&ec, i);
+ if (ret)
+ return ret;
+ list_for_each_entry(obj, &dev->netpolicy->obj_list[NETPOLICY_RX][i], list) {
+ i40e_set_itr_per_queue(vsi, &ec, obj->queue);
+ }
+ }
+ } else {
+ policy_param[NET_POLICY_BULK][NETPOLICY_RX] = NET_POLICY_BULK_RX;
+ policy_param[NET_POLICY_BULK][NETPOLICY_TX] = NET_POLICY_BULK_TX;
+ ret = i40e_fill_coalesce_for_policy(&ec, name);
+ if (ret)
+ return ret;
+ list_for_each_entry(obj, &dev->netpolicy->obj_list[NETPOLICY_RX][name], list) {
+ i40e_set_itr_per_queue(vsi, &ec, obj->queue);
+ }
}

return 0;
--
2.5.5