Measuring [buffer occupation / packet delay / thoughput.. ] withiproute2 and tc

Hi.

I've been working with tc and iproute, providing QoS mechanisms in my
LAN (HTB queue for example).

I want to measure performances and network troughputs, comparing Best
Effort Policy (FIFO) vs QoS Policy (HTB).

I wish to plot graphics [x: time / y:buffer_size] with N data flows, and
check them with my theoretical results (made by "Network
Simulator"/"OPNET"/...).

But *where* can i get the real data (latency, % buffer occupation and so
on) from? Does iproute2 provide counters where statistics are stored?

Any info & reference will be welcome.

replaying myself

> I wish to plot graphics [x: time / y:buffer_size] with N data flows, and
> check them with my theoretical results (made by "Network
> Simulator"/"OPNET"/...).
>
> But *where* can i get the real data (latency, % buffer occupation and so
> on) from? Does iproute2 provide counters where statistics are stored?

'til now, i have been focused to:
A. tc -s qdisc ls dev [interface]
B. iperf
C. ICMP's times