[ovs-dev] [ovs-discuss] OVS+DPDK QoS rate limit issue

[Lance Richardson]

> From: "王志克" <wangzhike at jd.com>
> To: ovs-dev at openvswitch.org, ovs-discuss at openvswitch.org
> Sent: Wednesday, August 23, 2017 11:41:05 PM
> Subject: [ovs-discuss] OVS+DPDK QoS rate limit issue
> 
> 
> 
> Hi All,
> 
> 
> 
> I am using OVS2.7.0 and DPDK 16.11, and testing rate limit function.
> 
> 
> 
> I found that if the policing_rate is set very large, say 5Gbps, the rate is
> limited dramatically to very low value, like 800Mbps.
> 
> The command is as below:
> 
> ovs-vsctl set interface port-7zel2so9sg ingress_policing_rate=5000000
> ingress_policing_burst=500000
> 
> 
> 
> If we set the rate lower than 4Gbps, the rate is limited correctly.
> 
> 
> 
> Test setup:
> 
> Sender (DPDK pktGen) sends out about 10Gbps udp packet, with size about 1420
> IP size.
> 
> The rate limit is set on VM vhost-user-client port.
> 
> 
> 
> Any idea about this issue? Is that known issue?
> 
> 

It seems 32-bit arithmetic is being used when converting the rate from
kilobits per second to bytes per second. Could you give this patch a try?

diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 1aaf6f7e2..d6ed2c7b0 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -2229,8 +2229,8 @@ netdev_dpdk_policer_construct(uint32_t rate, uint32_t burst)
     rte_spinlock_init(&policer->policer_lock);
 
     /* rte_meter requires bytes so convert kbits rate and burst to bytes. */
-    rate_bytes = rate * 1000/8;
-    burst_bytes = burst * 1000/8;
+    rate_bytes = rate * 1000ULL/8;
+    burst_bytes = burst * 1000ULL/8;
 
     policer->app_srtcm_params.cir = rate_bytes;
     policer->app_srtcm_params.cbs = burst_bytes;

Regards,

   Lance Richardson

> 
> Br,
> 
> Wang Zhike
> 
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