packet drop in p4 switches

[joyanta55]

Hello All,

In p4app I created a simple topology like:
h1->s1->s2->h2

And I tried to run h1 as TCP client and h2 as TCP server. I am using iperf to generate the traffic. Now here's the problem. From the dmesg command I can see a lot of packet transmission is happening, and I suspect the reason is packet drop. So I have two questions mainly:

• In the p4 code, is there any way so that I could come to know the packet has been dropped due to buffer overflow, I can see switch log file at the /tmp directory, but not sure what is the syntax to print/log info into those log files from the p4 code.

• Is there any way I can set the buffer size/ queue size from the p4 code for any switches. If yes, then how and what is the maximum limit for that.

Thanks in advance.