DPDK QoS performance issue in DPDK 1.4.1.

["Jim Jia" <mydpdk-KN7UnAbNpbg@public.gmane.org>]

 Hello, everyone!
      I have a question about DPDK's QoS Library performance. These days, I am tesing  DPDK's QoS Library performance using the DPDK example, qos_sched. Before I try to do the test,  I modified profile.cfg. In my opinion,  there should be no packet dropped  by qos_sched when it is processing packets at about 3Gbps, 64bit.  However, I find qos_sched would drop a few packets (about 30) at that case. Is it normal phenomenon? Or did I do anything wrong? I am so amazed in the results. I need help. Thanks a lot!

my profile.cfg  as following:

; Port configuration
[port]
frame overhead = 24
number of subports per port = 1
number of pipes per subport = 2
queue sizes = 64 64 64 64

; Subport configuration
[subport 0]
tb rate = 1250000000           ; Bytes per second
tb size = 1250000000             ; Bytes

tc 0 rate = 1250000000         ; Bytes per second
tc 1 rate = 1250000000         ; Bytes per second
tc 2 rate = 1250000000         ; Bytes per second
tc 3 rate = 1250000000         ; Bytes per second
tc period = 100000                 ; Milliseconds

pipe 0-1 = 0                ; These pipes are configured with pipe profile 0

; Pipe configuration
[pipe profile 0]
tb rate = 1250000000               ; Bytes per second
tb size = 1250000000           ; Bytes

tc 0 rate = 1250000000             ; Bytes per second
tc 1 rate = 1250000000         ; Bytes per second
tc 2 rate = 1250000000          ; Bytes per second
tc 3 rate = 1250000000         ; Bytes per second
tc period = 400000                 ; Milliseconds

tc 3 oversubscription weight = 1

tc 0 wrr weights = 1 1 1 1
tc 1 wrr weights = 1 1 1 1
tc 2 wrr weights = 1 1 1 1
tc 3 wrr weights = 1 1 1 1

; RED params per traffic class and color (Green / Yellow / Red)
[red]
tc 0 wred min = 48 40 32
tc 0 wred max = 64 64 64
tc 0 wred inv prob = 10 10 10
tc 0 wred weight = 9 9 9

tc 1 wred min = 48 40 32
tc 1 wred max = 64 64 64
tc 1 wred inv prob = 10 10 10
tc 1 wred weight = 9 9 9

tc 2 wred min = 48 40 32
tc 2 wred max = 64 64 64
tc 2 wred inv prob = 10 10 10
tc 2 wred weight = 9 9 9

tc 3 wred min = 48 40 32
tc 3 wred max = 64 64 64
tc 3 wred inv prob = 10 10 10
tc 3 wred weight = 9 9 9

Jim jia