diff options
| author | Jussi Maki <joamaki@gmail.com> | 2021-06-15 08:54:15 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-06-15 11:26:15 -0700 |
| commit | 848ca9182a7d25bb54955c3aab9a3a2742bf9678 (patch) | |
| tree | 15449c43a407368fbc404c5d79c5e4189840226e /drivers/net/bonding | |
| parent | b8f6b0522c298ae9267bd6584e19b942a0636910 (diff) | |
net: bonding: Use per-cpu rr_tx_counter
The round-robin rr_tx_counter was shared across CPUs leading to
significant cache thrashing at high packet rates. This patch switches
the round-robin packet counter to use a per-cpu variable to decide
the destination slave.
On a test with 2x100Gbit ICE nic with pktgen_sample_04_many_flows.sh
(-s 64 -t 32) the tx rate was 19.6Mpps before and 22.3Mpps after
this patch.
"perf top -e cache_misses" before:
12.31% [bonding] [k] bond_xmit_roundrobin_slave_get
10.59% [sch_fq_codel] [k] fq_codel_dequeue
9.34% [kernel] [k] skb_release_data
after:
15.42% [sch_fq_codel] [k] fq_codel_dequeue
10.06% [kernel] [k] __memset
9.12% [kernel] [k] skb_release_data
Signed-off-by: Jussi Maki <joamaki@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/bonding')
| -rw-r--r-- | drivers/net/bonding/bond_main.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index eb79a9f05914..1d9137e77dfc 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -4202,16 +4202,16 @@ static u32 bond_rr_gen_slave_id(struct bonding *bond) slave_id = prandom_u32(); break; case 1: - slave_id = bond->rr_tx_counter; + slave_id = this_cpu_inc_return(*bond->rr_tx_counter); break; default: reciprocal_packets_per_slave = bond->params.reciprocal_packets_per_slave; - slave_id = reciprocal_divide(bond->rr_tx_counter, + slave_id = this_cpu_inc_return(*bond->rr_tx_counter); + slave_id = reciprocal_divide(slave_id, reciprocal_packets_per_slave); break; } - bond->rr_tx_counter++; return slave_id; } @@ -4852,6 +4852,9 @@ static void bond_destructor(struct net_device *bond_dev) if (bond->wq) destroy_workqueue(bond->wq); + + if (bond->rr_tx_counter) + free_percpu(bond->rr_tx_counter); } void bond_setup(struct net_device *bond_dev) @@ -5350,6 +5353,15 @@ static int bond_init(struct net_device *bond_dev) if (!bond->wq) return -ENOMEM; + if (BOND_MODE(bond) == BOND_MODE_ROUNDROBIN) { + bond->rr_tx_counter = alloc_percpu(u32); + if (!bond->rr_tx_counter) { + destroy_workqueue(bond->wq); + bond->wq = NULL; + return -ENOMEM; + } + } + spin_lock_init(&bond->stats_lock); netdev_lockdep_set_classes(bond_dev); |