From: Jan Scheurich <jan.scheur...@ericsson.com>
Today dpif-netdev considers PMD threads on a non-local NUMA node for
automatic assignment of the rxqs of a port only if there are no local,
non-isolated PMDs.
On typical servers with both physical ports on one NUMA node, this
often
leaves the PMDs on the other NUMA node under-utilized, wasting CPU
resources. The alternative, to manually pin the rxqs to PMDs on remote
NUMA nodes, also has drawbacks as it limits OVS' ability to auto
load-balance the rxqs.
This patch introduces a new interface configuration option to allow
ports to be automatically polled by PMDs on any NUMA node:
ovs-vsctl set interface <Name> other_config:cross-numa-polling=true
If this option is not present or set to false, legacy behaviour
applies.
Signed-off-by: Jan Scheurich <jan.scheur...@ericsson.com>
Signed-off-by: Anurag Agarwal <anura...@gmail.com>
---
Documentation/topics/dpdk/pmd.rst | 24 ++++++++++++++++++++++--
lib/dpif-netdev.c | 31 +++++++++++++++++++++++--------
tests/pmd.at | 30 ++++++++++++++++++++++++++++++
vswitchd/vswitch.xml | 20 ++++++++++++++++++++
4 files changed, 95 insertions(+), 10 deletions(-)
diff --git a/Documentation/topics/dpdk/pmd.rst
b/Documentation/topics/dpdk/pmd.rst
index b259cc8b3..f6c9671d7 100644
--- a/Documentation/topics/dpdk/pmd.rst
+++ b/Documentation/topics/dpdk/pmd.rst
@@ -132,8 +132,28 @@ or can be triggered by using::
Port/Rx Queue assignment to PMD threads by manual pinning
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Rx queues may be manually pinned to cores. This will change the default Rx
-queue assignment to PMD threads::
+
+Normally, Rx queues are assigned to PMD threads automatically. By default
+OVS only assigns Rx queues to PMD threads executing on the same NUMA
+node in order to avoid unnecessary latency for accessing packet buffers
+across the NUMA boundary. Typically this overhead is higher for vhostuser
+ports than for physical ports due to the packet copy that is done for all
+rx packets.
+
+On NUMA servers with physical ports only on one NUMA node, the NUMA-local
+polling policy can lead to an under-utilization of the PMD threads on the
+remote NUMA node. For the overall OVS performance it may in such cases be
+beneficial to utilize the spare capacity and allow polling of a physical
+port's rxqs across NUMA nodes despite the overhead involved.
+The policy can be set per port with the following configuration option::
+
+ $ ovs-vsctl set Interface <iface> \
+ other_config:cross-numa-polling=true|false
+
+The default value is false.
+
+Rx queues may also be manually pinned to cores. This will change the default
+Rx queue assignment to PMD threads::
$ ovs-vsctl set Interface <iface> \
other_config:pmd-rxq-affinity=<rxq-affinity-list>
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 720818e30..4fda8d7a0 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -466,6 +466,7 @@ struct dp_netdev_port {
char *type; /* Port type as requested by user. */
char *rxq_affinity_list; /* Requested affinity of rx queues. */
enum txq_req_mode txq_requested_mode;
+ bool cross_numa_polling; /* If true cross polling will be enabled */
};
static bool dp_netdev_flow_ref(struct dp_netdev_flow *);
@@ -5018,6 +5019,7 @@ dpif_netdev_port_set_config(struct dpif *dpif, odp_port_t
port_no,
bool emc_enabled = smap_get_bool(cfg, "emc-enable", true);
const char *tx_steering_mode = smap_get(cfg, "tx-steering");
enum txq_req_mode txq_mode;
+ bool cross_numa_polling = smap_get_bool(cfg, "cross-numa-polling", false);
ovs_rwlock_wrlock(&dp->port_rwlock);
error = get_port_by_number(dp, port_no, &port);
@@ -5086,6 +5088,14 @@ dpif_netdev_port_set_config(struct dpif *dpif,
odp_port_t port_no,
dp_netdev_request_reconfigure(dp);
}
+ if (cross_numa_polling != port->cross_numa_polling) {
+ port->cross_numa_polling = cross_numa_polling;
+ VLOG_INFO("%s:cross-numa-polling has been %s.",
+ netdev_get_name(port->netdev),
+ (cross_numa_polling)? "enabled" : "disabled");
+ dp_netdev_request_reconfigure(dp);
+ }
+
unlock:
ovs_rwlock_unlock(&dp->port_rwlock);
return error;
@@ -5885,7 +5895,7 @@ sched_numa_list_schedule(struct sched_numa_list
*numa_list,
{
struct dp_netdev_port *port;
struct dp_netdev_rxq **rxqs = NULL;
- struct sched_numa *last_cross_numa;
+ struct sched_numa *next_numa = NULL;
unsigned n_rxqs = 0;
bool start_logged = false;
size_t n_numa;
@@ -5969,7 +5979,7 @@ sched_numa_list_schedule(struct sched_numa_list
*numa_list,
qsort(rxqs, n_rxqs, sizeof *rxqs, compare_rxq_cycles);
}
- last_cross_numa = NULL;
+ next_numa = NULL;
n_numa = sched_numa_list_count(numa_list);
for (unsigned i = 0; i < n_rxqs; i++) {
struct dp_netdev_rxq *rxq = rxqs[i];
@@ -5989,20 +5999,25 @@ sched_numa_list_schedule(struct sched_numa_list
*numa_list,
proc_cycles = dp_netdev_rxq_get_cycles(rxq, RXQ_CYCLES_PROC_HIST);
/* Select the numa that should be used for this rxq. */
numa_id = netdev_get_numa_id(rxq->port->netdev);
- numa = sched_numa_list_lookup(numa_list, numa_id);
+
+ if (!(rxqs[i]->port->cross_numa_polling)) {
+ /* Try to find a local pmd. */
+ numa = sched_numa_list_lookup(numa_list, numa_id);
+ } else {
+ /* Allow polling by any pmd. */
+ numa = NULL;
+ }
/* Check if numa has no PMDs or no non-isolated PMDs. */
if (!numa || !sched_numa_noniso_pmd_count(numa)) {
/* Unable to use this numa to find a PMD. */
- numa = NULL;
/* Find any numa with available PMDs. */
for (int j = 0; j < n_numa; j++) {
- numa = sched_numa_list_next(numa_list, last_cross_numa);
- if (sched_numa_noniso_pmd_count(numa)) {
+ next_numa = sched_numa_list_next(numa_list, next_numa);
+ if (sched_numa_noniso_pmd_count(next_numa)) {
+ numa = next_numa;
break;
}
- last_cross_numa = numa;
- numa = NULL;
}
}
diff --git a/tests/pmd.at b/tests/pmd.at
index a2f9d34a2..81a9a0eca 100644
--- a/tests/pmd.at
+++ b/tests/pmd.at
@@ -541,6 +541,36 @@
icmp,vlan_tci=0x0000,dl_src=50:54:00:00:00:09,dl_dst=50:54:00:00:00:0a,nw_src=10
OVS_VSWITCHD_STOP
AT_CLEANUP
+AT_SETUP([PMD - Enable cross numa polling])
+OVS_VSWITCHD_START(
+ [add-port br0 p1 -- set Interface p1 type=dummy-pmd ofport_request=1
options:n_rxq=4 -- \
+ set Open_vSwitch . other_config:pmd-cpu-mask=3
+], [], [], [--dummy-numa 0,1])
+
+AT_CHECK([ovs-ofctl add-flow br0 action=controller])
+
+AT_CHECK([ovs-appctl dpif-netdev/pmd-rxq-show | parse_pmd_rxq_show | cut -f 3
-d ' ' | sort | uniq], [0], [dnl
+0
+])
+
+dnl Enable cross numa polling and check numa ids
+AT_CHECK([ovs-vsctl set Interface p1 other_config:cross-numa-polling=true])
+
+AT_CHECK([ovs-appctl dpif-netdev/pmd-rxq-show | parse_pmd_rxq_show | cut -f 3
-d ' ' | sort | uniq], [0], [dnl
+0
+1
+])
+
+dnl Disable cross numa polling and check numa ids
+AT_CHECK([ovs-vsctl set Interface p1 other_config:cross-numa-polling=false])
+
+AT_CHECK([ovs-appctl dpif-netdev/pmd-rxq-show | parse_pmd_rxq_show | cut -f 3
-d ' ' | sort | uniq], [0], [dnl
+0
+])
+
+OVS_VSWITCHD_STOP(["/|WARN|/d"])
+AT_CLEANUP
+
AT_SETUP([PMD - change numa node])
OVS_VSWITCHD_START(
[add-port br0 p1 -- set Interface p1 type=dummy-pmd ofport_request=1
options:n_rxq=2 -- \
diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index 0c6632617..4d7339885 100644
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -3284,6 +3284,26 @@ ovs-vsctl add-port br0 p0 -- set Interface p0 type=patch
options:peer=p1 \
</p>
</column>
+ <column name="other_config" key="cross-numa-polling"
+ type='{"type": "boolean"}'>
+ <p>
+ Specifies if the RX queues of the port can be automatically assigned
+ to PMD threads on any NUMA node or only on the local NUMA node of
+ the port.
+ </p>
+ <p>
+ Polling of physical ports from a non-local PMD thread incurs some
+ performance penalty due to the access to packet data across the NUMA
+ barrier. This option can still increase the overall performance if
+ it allows better utilization of those non-local PMDs threads.
+ It is most useful together with the auto load-balancing of RX queues
+ (see other_config:auto_lb in table Open_vSwitch).
+ </p>
+ <p>
+ Defaults to false.
+ </p>
+ </column>
+
<column name="options" key="xdp-mode"
type='{"type": "string",
"enum": ["set", ["best-effort", "native-with-zerocopy",
--
2.25.1
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