@@ -585,13 +585,19 @@ mode
balance-tlb or 5
Adaptive transmit load balancing: channel bonding that
- does not require any special switch support. The
- outgoing traffic is distributed according to the
- current load (computed relative to the speed) on each
- slave. Incoming traffic is received by the current
- slave. If the receiving slave fails, another slave
- takes over the MAC address of the failed receiving
- slave.
+ does not require any special switch support.
+
+ In tlb_dynamic_lb=1 mode; the outgoing traffic is
+ distributed according to the current load (computed
+ relative to the speed) on each slave.
+
+ In tlb_dynamic_lb=0 mode; the load balancing based on
+ current load is disabled and the load is distributed
+ only using the hash distribution.
+
+ Incoming traffic is received by the current slave.
+ If the receiving slave fails, another slave takes over
+ the MAC address of the failed receiving slave.
Prerequisite:
@@ -736,6 +742,28 @@ primary_reselect
This option was added for bonding version 3.6.0.
+tlb_dynamic_lb
+
+ Specifies if dynamic shuffling of flows is enabled in tlb
+ mode. The value has no effect on any other modes.
+
+ The default behavior of tlb mode is to shuffle active flows across
+ slaves based on the load in that interval. This gives nice lb
+ characteristics but can cause packet reordering. If re-ordering is
+ a concern use this variable to disable flow shuffling and rely on
+ load balancing provided solely by the hash distribution.
+ xmit-hash-policy can be used to select the appropriate hashing for
+ the setup.
+
+ The sysfs entry can be used to change the setting per bond device
+ and the initial value is derived from the module parameter. The
+ sysfs entry is allowed to be changed only if the bond device is
+ down.
+
+ The default value is "1" that enables flow shuffling while value "0"
+ disables it. This option was added in bonding driver 3.7.1
+
+
updelay
Specifies the time, in milliseconds, to wait before enabling a
@@ -1356,7 +1356,8 @@ static int bond_do_alb_xmit(struct sk_buff *skb, struct bonding *bond,
if (!tx_slave) {
/* unbalanced or unassigned, send through primary */
tx_slave = rcu_dereference(bond->curr_active_slave);
- bond_info->unbalanced_load += skb->len;
+ if (bond->params.tlb_dynamic_lb)
+ bond_info->unbalanced_load += skb->len;
}
if (tx_slave && SLAVE_IS_OK(tx_slave)) {
@@ -1369,7 +1370,7 @@ static int bond_do_alb_xmit(struct sk_buff *skb, struct bonding *bond,
goto out;
}
- if (tx_slave) {
+ if (tx_slave && bond->params.tlb_dynamic_lb) {
_lock_tx_hashtbl(bond);
__tlb_clear_slave(bond, tx_slave, 0);
_unlock_tx_hashtbl(bond);
@@ -1399,11 +1400,21 @@ int bond_tlb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
/* In case of IPX, it will falback to L2 hash */
case htons(ETH_P_IPV6):
hash_index = bond_xmit_hash(bond, skb);
- tx_slave = tlb_choose_channel(bond, hash_index & 0xFF, skb->len);
+ if (bond->params.tlb_dynamic_lb) {
+ tx_slave = tlb_choose_channel(bond,
+ hash_index & 0xFF,
+ skb->len);
+ } else {
+ struct list_head *iter;
+ int idx = hash_index % bond->slave_cnt;
+
+ bond_for_each_slave_rcu(bond, tx_slave, iter)
+ if (--idx < 0)
+ break;
+ }
break;
}
}
-
return bond_do_alb_xmit(skb, bond, tx_slave);
}
@@ -3096,7 +3096,8 @@ static int bond_open(struct net_device *bond_dev)
*/
if (bond_alb_initialize(bond, (bond->params.mode == BOND_MODE_ALB)))
return -ENOMEM;
- queue_delayed_work(bond->wq, &bond->alb_work, 0);
+ if (bond->params.tlb_dynamic_lb)
+ queue_delayed_work(bond->wq, &bond->alb_work, 0);
}
if (bond->params.miimon) /* link check interval, in milliseconds. */
@@ -4304,6 +4305,7 @@ static int bond_check_params(struct bond_params *params)
params->min_links = min_links;
params->lp_interval = lp_interval;
params->packets_per_slave = packets_per_slave;
+ params->tlb_dynamic_lb = 1; /* Default value */
if (packets_per_slave > 0) {
params->reciprocal_packets_per_slave =
reciprocal_value(packets_per_slave);
@@ -70,6 +70,8 @@ static int bond_option_mode_set(struct bonding *bond,
const struct bond_opt_value *newval);
static int bond_option_slaves_set(struct bonding *bond,
const struct bond_opt_value *newval);
+static int bond_option_tlb_dynamic_lb_set(struct bonding *bond,
+ const struct bond_opt_value *newval);
static const struct bond_opt_value bond_mode_tbl[] = {
@@ -179,6 +181,12 @@ static const struct bond_opt_value bond_lp_interval_tbl[] = {
{ NULL, -1, 0},
};
+static const struct bond_opt_value bond_tlb_dynamic_lb_tbl[] = {
+ { "off", 0, 0},
+ { "on", 1, BOND_VALFLAG_DEFAULT},
+ { NULL, -1, 0}
+};
+
static const struct bond_option bond_opts[] = {
[BOND_OPT_MODE] = {
.id = BOND_OPT_MODE,
@@ -364,6 +372,15 @@ static const struct bond_option bond_opts[] = {
.flags = BOND_OPTFLAG_RAWVAL,
.set = bond_option_slaves_set
},
+ [BOND_OPT_TLB_DYNAMIC_LB] = {
+ .id = BOND_OPT_TLB_DYNAMIC_LB,
+ .name = "dynamic_lb",
+ .desc = "Enable dynamic flow shuffling",
+ .unsuppmodes = BOND_MODE_ALL_EX(BIT(BOND_MODE_TLB)),
+ .values = bond_tlb_dynamic_lb_tbl,
+ .flags = BOND_OPTFLAG_IFDOWN,
+ .set = bond_option_tlb_dynamic_lb_set,
+ },
{ }
};
@@ -1337,3 +1354,13 @@ err_no_cmd:
ret = -EPERM;
goto out;
}
+
+static int bond_option_tlb_dynamic_lb_set(struct bonding *bond,
+ const struct bond_opt_value *newval)
+{
+ pr_info("%s: Setting dynamic-lb to %s (%llu)\n",
+ bond->dev->name, newval->string, newval->value);
+ bond->params.tlb_dynamic_lb = newval->value;
+
+ return 0;
+}
@@ -62,6 +62,7 @@ enum {
BOND_OPT_RESEND_IGMP,
BOND_OPT_LP_INTERVAL,
BOND_OPT_SLAVES,
+ BOND_OPT_TLB_DYNAMIC_LB,
BOND_OPT_LAST
};
@@ -1039,6 +1039,34 @@ static ssize_t bonding_store_lp_interval(struct device *d,
static DEVICE_ATTR(lp_interval, S_IRUGO | S_IWUSR,
bonding_show_lp_interval, bonding_store_lp_interval);
+static ssize_t bonding_show_tlb_dynamic_lb(struct device *d,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct bonding *bond = to_bond(d);
+ return sprintf(buf, "%d\n", bond->params.tlb_dynamic_lb);
+}
+
+static ssize_t bonding_store_tlb_dynamic_lb(struct device *d,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ struct bonding *bond = to_bond(d);
+ int ret;
+
+ ret = bond_opt_tryset_rtnl(bond, BOND_OPT_TLB_DYNAMIC_LB,
+ (char *)buf);
+ if (!ret)
+ ret = count;
+
+ return ret;
+}
+
+static DEVICE_ATTR(tlb_dynamic_lb, S_IRUGO | S_IWUSR,
+ bonding_show_tlb_dynamic_lb,
+ bonding_store_tlb_dynamic_lb);
+
static ssize_t bonding_show_packets_per_slave(struct device *d,
struct device_attribute *attr,
char *buf)
@@ -1099,6 +1127,7 @@ static struct attribute *per_bond_attrs[] = {
&dev_attr_min_links.attr,
&dev_attr_lp_interval.attr,
&dev_attr_packets_per_slave.attr,
+ &dev_attr_tlb_dynamic_lb.attr,
NULL,
};
@@ -174,6 +174,7 @@ struct bond_params {
int resend_igmp;
int lp_interval;
int packets_per_slave;
+ int tlb_dynamic_lb;
struct reciprocal_value reciprocal_packets_per_slave;
};
The aggresive load balancing causes packet re-ordering as active flows are moved from a slave to another within the group. Sometime this aggresive lb is not necessary if the preference is for less re-ordering. This parameter if used with value "0" disables this dynamic flow shuffling minimizing packet re-ordering. Of course the side effect is that it has to live with the static load balancing that the hashing distribution provides. This impact is less severe if the correct xmit-hashing-policy is used for the tlb setup. The default value of the parameter is set to "1" mimicing the earlier behavior. Ran the netperf test with 200 stream for 1 min between two hosts with 4x1G trunk (xmit-lb mode with xmit-policy L3+4) before and after these changes. Following was the command used for those 200 instances - netperf -t TCP_RR -l 60 -s 5 -H <host> -- -r81920,81920 Transactions per second: Before change: 1,367.11 After change: 1,470.65 Change-Id: Ie3f75c77282cf602e83a6e833c6eb164e72a0990 Signed-off-by: Mahesh Bandewar <maheshb@google.com> --- v2: [Trivial] Commit log update with the proper workload and perf numbers. v3: [Trivial] Styling changes. Simplified set() by using built-in BOND_OPTFLAG_IFDOWN flag. v4: tlb_dynamic_lb is no longer a module parameter Removed conditional work-queue initialization/cancellation for lb mode. [Trivial] Styling changes. [Trivial] Documentation changes. Documentation/networking/bonding.txt | 42 ++++++++++++++++++++++++++++++------ drivers/net/bonding/bond_alb.c | 19 ++++++++++++---- drivers/net/bonding/bond_main.c | 4 +++- drivers/net/bonding/bond_options.c | 27 +++++++++++++++++++++++ drivers/net/bonding/bond_options.h | 1 + drivers/net/bonding/bond_sysfs.c | 29 +++++++++++++++++++++++++ drivers/net/bonding/bonding.h | 1 + 7 files changed, 111 insertions(+), 12 deletions(-)