forked from mirrors/linux
net: openvswitch: reorder masks array based on usage
This patch reorders the masks array every 4 seconds based on their usage count. This greatly reduces the masks per packet hit, and hence the overall performance. Especially in the OVS/OVN case for OpenShift. Here are some results from the OVS/OVN OpenShift test, which use 8 pods, each pod having 512 uperf connections, each connection sends a 64-byte request and gets a 1024-byte response (TCP). All uperf clients are on 1 worker node while all uperf servers are on the other worker node. Kernel without this patch : 7.71 Gbps Kernel with this patch applied: 14.52 Gbps We also run some tests to verify the rebalance activity does not lower the flow insertion rate, which does not. Signed-off-by: Eelco Chaudron <echaudro@redhat.com> Tested-by: Andrew Theurer <atheurer@redhat.com> Reviewed-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eelco Chaudron
David S. Miller
parent
b18432c5a4
commit
eac87c413b
4 changed files with 207 additions and 7 deletions
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@ -130,6 +130,8 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *,
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const struct dp_upcall_info *,
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uint32_t cutlen);
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static void ovs_dp_masks_rebalance(struct work_struct *work);
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/* Must be called with rcu_read_lock or ovs_mutex. */
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const char *ovs_dp_name(const struct datapath *dp)
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{
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@ -1653,6 +1655,7 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
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goto err_destroy_reply;
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ovs_dp_set_net(dp, sock_net(skb->sk));
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INIT_DELAYED_WORK(&dp->masks_rebalance, ovs_dp_masks_rebalance);
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/* Allocate table. */
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err = ovs_flow_tbl_init(&dp->table);
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@ -1712,6 +1715,9 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
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ovs_net = net_generic(ovs_dp_get_net(dp), ovs_net_id);
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list_add_tail_rcu(&dp->list_node, &ovs_net->dps);
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schedule_delayed_work(&dp->masks_rebalance,
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msecs_to_jiffies(DP_MASKS_REBALANCE_INTERVAL));
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ovs_unlock();
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ovs_notify(&dp_datapath_genl_family, reply, info);
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@ -1756,6 +1762,9 @@ static void __dp_destroy(struct datapath *dp)
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/* RCU destroy the flow table */
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call_rcu(&dp->rcu, destroy_dp_rcu);
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/* Cancel remaining work. */
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cancel_delayed_work_sync(&dp->masks_rebalance);
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}
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static int ovs_dp_cmd_del(struct sk_buff *skb, struct genl_info *info)
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@ -2338,6 +2347,19 @@ static int ovs_vport_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb)
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return skb->len;
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}
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static void ovs_dp_masks_rebalance(struct work_struct *work)
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{
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struct datapath *dp = container_of(work, struct datapath,
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masks_rebalance.work);
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ovs_lock();
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ovs_flow_masks_rebalance(&dp->table);
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ovs_unlock();
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schedule_delayed_work(&dp->masks_rebalance,
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msecs_to_jiffies(DP_MASKS_REBALANCE_INTERVAL));
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}
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static const struct nla_policy vport_policy[OVS_VPORT_ATTR_MAX + 1] = {
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[OVS_VPORT_ATTR_NAME] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 },
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[OVS_VPORT_ATTR_STATS] = { .len = sizeof(struct ovs_vport_stats) },
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@ -20,8 +20,9 @@
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#include "meter.h"
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#include "vport-internal_dev.h"
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#define DP_MAX_PORTS USHRT_MAX
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#define DP_VPORT_HASH_BUCKETS 1024
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#define DP_MAX_PORTS USHRT_MAX
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#define DP_VPORT_HASH_BUCKETS 1024
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#define DP_MASKS_REBALANCE_INTERVAL 4000
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/**
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* struct dp_stats_percpu - per-cpu packet processing statistics for a given
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@ -83,6 +84,9 @@ struct datapath {
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/* Switch meters. */
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struct dp_meter_table meter_tbl;
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/* re-balance flow masks timer */
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struct delayed_work masks_rebalance;
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};
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/**
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@ -29,6 +29,7 @@
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#include <linux/icmp.h>
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#include <linux/icmpv6.h>
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#include <linux/rculist.h>
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#include <linux/sort.h>
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#include <net/ip.h>
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#include <net/ipv6.h>
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#include <net/ndisc.h>
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@ -169,16 +170,70 @@ static struct table_instance *table_instance_alloc(int new_size)
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return ti;
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}
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static void __mask_array_destroy(struct mask_array *ma)
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{
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free_percpu(ma->masks_usage_cntr);
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kfree(ma);
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}
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static void mask_array_rcu_cb(struct rcu_head *rcu)
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{
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struct mask_array *ma = container_of(rcu, struct mask_array, rcu);
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__mask_array_destroy(ma);
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}
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static void tbl_mask_array_reset_counters(struct mask_array *ma)
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{
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int i, cpu;
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/* As the per CPU counters are not atomic we can not go ahead and
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* reset them from another CPU. To be able to still have an approximate
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* zero based counter we store the value at reset, and subtract it
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* later when processing.
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*/
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for (i = 0; i < ma->max; i++) {
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ma->masks_usage_zero_cntr[i] = 0;
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for_each_possible_cpu(cpu) {
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u64 *usage_counters = per_cpu_ptr(ma->masks_usage_cntr,
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cpu);
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unsigned int start;
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u64 counter;
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do {
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start = u64_stats_fetch_begin_irq(&ma->syncp);
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counter = usage_counters[i];
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} while (u64_stats_fetch_retry_irq(&ma->syncp, start));
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ma->masks_usage_zero_cntr[i] += counter;
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}
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}
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}
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static struct mask_array *tbl_mask_array_alloc(int size)
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{
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struct mask_array *new;
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size = max(MASK_ARRAY_SIZE_MIN, size);
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new = kzalloc(sizeof(struct mask_array) +
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sizeof(struct sw_flow_mask *) * size, GFP_KERNEL);
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sizeof(struct sw_flow_mask *) * size +
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sizeof(u64) * size, GFP_KERNEL);
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if (!new)
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return NULL;
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new->masks_usage_zero_cntr = (u64 *)((u8 *)new +
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sizeof(struct mask_array) +
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sizeof(struct sw_flow_mask *) *
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size);
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new->masks_usage_cntr = __alloc_percpu(sizeof(u64) * size,
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__alignof__(u64));
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if (!new->masks_usage_cntr) {
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kfree(new);
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return NULL;
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}
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new->count = 0;
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new->max = size;
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@ -202,10 +257,10 @@ static int tbl_mask_array_realloc(struct flow_table *tbl, int size)
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if (ovsl_dereference(old->masks[i]))
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new->masks[new->count++] = old->masks[i];
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}
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call_rcu(&old->rcu, mask_array_rcu_cb);
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}
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rcu_assign_pointer(tbl->mask_array, new);
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kfree_rcu(old, rcu);
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return 0;
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}
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@ -223,6 +278,11 @@ static int tbl_mask_array_add_mask(struct flow_table *tbl,
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return err;
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ma = ovsl_dereference(tbl->mask_array);
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} else {
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/* On every add or delete we need to reset the counters so
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* every new mask gets a fair chance of being prioritized.
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*/
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tbl_mask_array_reset_counters(ma);
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}
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BUG_ON(ovsl_dereference(ma->masks[ma_count]));
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@ -260,6 +320,9 @@ static void tbl_mask_array_del_mask(struct flow_table *tbl,
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if (ma->max >= (MASK_ARRAY_SIZE_MIN * 2) &&
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ma_count <= (ma->max / 3))
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tbl_mask_array_realloc(tbl, ma->max / 2);
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else
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tbl_mask_array_reset_counters(ma);
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}
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/* Remove 'mask' from the mask list, if it is not needed any more. */
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@ -312,7 +375,7 @@ int ovs_flow_tbl_init(struct flow_table *table)
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free_ti:
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__table_instance_destroy(ti);
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free_mask_array:
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kfree(ma);
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__mask_array_destroy(ma);
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free_mask_cache:
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free_percpu(table->mask_cache);
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return -ENOMEM;
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@ -392,7 +455,7 @@ void ovs_flow_tbl_destroy(struct flow_table *table)
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struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti);
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free_percpu(table->mask_cache);
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kfree_rcu(rcu_dereference_raw(table->mask_array), rcu);
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call_rcu(&table->mask_array->rcu, mask_array_rcu_cb);
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table_instance_destroy(table, ti, ufid_ti, false);
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}
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@ -606,6 +669,7 @@ static struct sw_flow *flow_lookup(struct flow_table *tbl,
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u32 *n_mask_hit,
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u32 *index)
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{
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u64 *usage_counters = this_cpu_ptr(ma->masks_usage_cntr);
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struct sw_flow *flow;
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struct sw_flow_mask *mask;
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int i;
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@ -614,8 +678,12 @@ static struct sw_flow *flow_lookup(struct flow_table *tbl,
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mask = rcu_dereference_ovsl(ma->masks[*index]);
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if (mask) {
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flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
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if (flow)
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if (flow) {
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u64_stats_update_begin(&ma->syncp);
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usage_counters[*index]++;
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u64_stats_update_end(&ma->syncp);
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return flow;
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}
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}
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}
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@ -631,6 +699,9 @@ static struct sw_flow *flow_lookup(struct flow_table *tbl,
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flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
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if (flow) { /* Found */
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*index = i;
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u64_stats_update_begin(&ma->syncp);
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usage_counters[*index]++;
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u64_stats_update_end(&ma->syncp);
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return flow;
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}
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}
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@ -934,6 +1005,98 @@ int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow,
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return 0;
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}
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static int compare_mask_and_count(const void *a, const void *b)
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{
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const struct mask_count *mc_a = a;
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const struct mask_count *mc_b = b;
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return (s64)mc_b->counter - (s64)mc_a->counter;
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}
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/* Must be called with OVS mutex held. */
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void ovs_flow_masks_rebalance(struct flow_table *table)
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{
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struct mask_array *ma = rcu_dereference_ovsl(table->mask_array);
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struct mask_count *masks_and_count;
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struct mask_array *new;
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int masks_entries = 0;
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int i;
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/* Build array of all current entries with use counters. */
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masks_and_count = kmalloc_array(ma->max, sizeof(*masks_and_count),
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GFP_KERNEL);
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if (!masks_and_count)
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return;
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for (i = 0; i < ma->max; i++) {
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struct sw_flow_mask *mask;
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unsigned int start;
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int cpu;
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mask = rcu_dereference_ovsl(ma->masks[i]);
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if (unlikely(!mask))
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break;
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masks_and_count[i].index = i;
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masks_and_count[i].counter = 0;
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for_each_possible_cpu(cpu) {
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u64 *usage_counters = per_cpu_ptr(ma->masks_usage_cntr,
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cpu);
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u64 counter;
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do {
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start = u64_stats_fetch_begin_irq(&ma->syncp);
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counter = usage_counters[i];
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} while (u64_stats_fetch_retry_irq(&ma->syncp, start));
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masks_and_count[i].counter += counter;
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}
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/* Subtract the zero count value. */
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masks_and_count[i].counter -= ma->masks_usage_zero_cntr[i];
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/* Rather than calling tbl_mask_array_reset_counters()
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* below when no change is needed, do it inline here.
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*/
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ma->masks_usage_zero_cntr[i] += masks_and_count[i].counter;
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}
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if (i == 0)
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goto free_mask_entries;
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/* Sort the entries */
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masks_entries = i;
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sort(masks_and_count, masks_entries, sizeof(*masks_and_count),
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compare_mask_and_count, NULL);
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/* If the order is the same, nothing to do... */
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for (i = 0; i < masks_entries; i++) {
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if (i != masks_and_count[i].index)
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break;
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}
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if (i == masks_entries)
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goto free_mask_entries;
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/* Rebuilt the new list in order of usage. */
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new = tbl_mask_array_alloc(ma->max);
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if (!new)
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goto free_mask_entries;
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for (i = 0; i < masks_entries; i++) {
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int index = masks_and_count[i].index;
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new->masks[new->count++] =
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rcu_dereference_ovsl(ma->masks[index]);
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}
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rcu_assign_pointer(table->mask_array, new);
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call_rcu(&ma->rcu, mask_array_rcu_cb);
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free_mask_entries:
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kfree(masks_and_count);
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}
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/* Initializes the flow module.
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* Returns zero if successful or a negative error code. */
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int ovs_flow_init(void)
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@ -27,9 +27,17 @@ struct mask_cache_entry {
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u32 mask_index;
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};
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struct mask_count {
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int index;
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u64 counter;
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};
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struct mask_array {
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struct rcu_head rcu;
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int count, max;
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u64 __percpu *masks_usage_cntr;
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u64 *masks_usage_zero_cntr;
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struct u64_stats_sync syncp;
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struct sw_flow_mask __rcu *masks[];
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};
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@ -86,4 +94,7 @@ bool ovs_flow_cmp(const struct sw_flow *, const struct sw_flow_match *);
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void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src,
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bool full, const struct sw_flow_mask *mask);
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void ovs_flow_masks_rebalance(struct flow_table *table);
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#endif /* flow_table.h */
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