-----Original Message-----
From: <[email protected]> on behalf of Bhanuprakash Bodireddy
<[email protected]>
Date: Thursday, June 29, 2017 at 3:39 PM
To: "[email protected]" <[email protected]>
Subject: [ovs-dev] [PATCH v3 6/6] dpif-netdev: Flush the packets in
intermediate queue.
Under low rate traffic conditions, there can be 2 issues.
(1) Packets potentially can get stuck in the intermediate queue.
(2) Latency of the packets can increase significantly due to
buffering in intermediate queue.
This commit handles the (1) issue by flushing the tx port queues from
PMD processing loop. Also this commit addresses issue (2) by flushing
the tx queues after every rxq port processing. This reduces the latency
with out impacting the forwarding throughput.
MASTER
--------
Pkt size min(ns) avg(ns) max(ns)
512 4,631 5,022 309,914
1024 5,545 5,749 104,294
1280 5,978 6,159 45,306
1518 6,419 6,774 946,850
MASTER + COMMIT
-----------------
Pkt size min(ns) avg(ns) max(ns)
512 4,711 5,064 182,477
1024 5,601 5,888 701,654
1280 6,018 6,491 533,037
1518 6,467 6,734 312,471
PMDs can be teared down and spawned at runtime and so the rxq and txq
mapping of the PMD threads can change. In few cases packets can get
stuck in the queue due to reconfiguration and this commit helps flush
the queues.
Suggested-by: Eelco Chaudron <[email protected]>
Reported-at:
https://urldefense.proofpoint.com/v2/url?u=https-3A__mail.openvswitch.org_pipermail_ovs-2Ddev_2017-2DApril_331039.html&d=DwICAg&c=uilaK90D4TOVoH58JNXRgQ&r=BVhFA09CGX7JQ5Ih-uZnsw&m=bHrBe9xQ4KZyIP8eXmMQgmAki-7TrHqH1PHcy7KBp9M&s=FLHjFbETDpuejnwNxIJem8vPtHo7KDb0q0YJSIpsMb8&e=
Signed-off-by: Bhanuprakash Bodireddy <[email protected]>
Signed-off-by: Antonio Fischetti <[email protected]>
Co-authored-by: Antonio Fischetti <[email protected]>
Signed-off-by: Markus Magnusson <[email protected]>
Co-authored-by: Markus Magnusson <[email protected]>
Acked-by: Eelco Chaudron <[email protected]>
---
lib/dpif-netdev.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 7e1f5bc..f03bd3e 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -3603,6 +3603,8 @@ dpif_netdev_run(struct dpif *dpif)
for (i = 0; i < port->n_rxq; i++) {
dp_netdev_process_rxq_port(non_pmd, port->rxqs[i].rx,
port->port_no);
+
+ dp_netdev_flush_txq_ports(non_pmd);
Is this a temporary change ?; seems counter to the objective ?
Should be latency based, as discussed on another thread couple months ago ?;
configurable by port type and port ?
}
}
}
@@ -3760,6 +3762,8 @@ reload:
for (i = 0; i < poll_cnt; i++) {
dp_netdev_process_rxq_port(pmd, poll_list[i].rx,
poll_list[i].port_no);
+
+ dp_netdev_flush_txq_ports(pmd);
}
Same comment as above.
if (lc++ > 1024) {
@@ -3780,6 +3784,9 @@ reload:
}
}
+ /* Flush the queues as part of reconfiguration logic. */
+ dp_netdev_flush_txq_ports(pmd);
+
poll_cnt = pmd_load_queues_and_ports(pmd, &poll_list);
exiting = latch_is_set(&pmd->exit_latch);
/* Signal here to make sure the pmd finishes
--
2.4.11
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