MikroTik

Does RouterOS expose the functionality to view and manipulate the TX queue length for various hardware interfaces?
That includes queues in the general OS interface stack, device driver specific queues and perhaps even hardware queues in the interfaces itself.

What I am looking for is an equivalent to setting txqueuelen under Linux with either ifconfig or ip.

To further elaborate on this, with 'hardware queue' I mean the value displayed with ethtool -g under Linux (and settable with ethtool -G).

there was a issue that related to queue sizes of the ethernet controller, in this case it was the RX queue which was of unknown size & not changeable, and led to packet loss. see http://forum.mikrotik.com/viewtopic.php?f=2&t=46764

i'm not aware of any way to obtain RX/TX queue sizes, nor whether they are changeable. there was also no reply in this forum.

My tips for performance on vmware:

ESX(i)
Use ESX/ESXi instead of Server/Workstation.

e1000
Make sure the virtual machine gets Intel (e1000) virtual ethernet instead of AMD (vlance).
They say the trick is setting the guest to a 64 bit type. You can also manually do a ethernet0.virtualDev = "e1000"
Else you'll see a lot of "dropped" packets in Interfaces, and packet loss on simple things like pings.

Queue sizes
If you use queue trees make sure the queue types are big enough.
Else you'll see a lot of "dropped" packets in Queue Tree (if you enable "Dropped" colum) for queues that are not saturated, and packet loss on simple things like pings.

Rx buffers
If you use queuing at all and have more than 150Mb per interface you may also experiment silent packet drops (like in pings). This is happening at the vmware's vSwitch level, and you can check it with the "esxtop" tool (column DRPRX).
The solution to this is increasing the RX buffer of the (virtual) ethernet card with ethtool or modprobe parameters. Unfortunately there is no nice way to do this.
I have experimentally edited the binary driver and changed default value from 256 to 2048 and got it ok by now with at least 300Mb.