Tuning for NTttcp
NTttcp is a Winsock-based port of ttcp to Windows. It helps measure network driver performance and throughput on different network topologies and hardware setups. It provides the customer with a multithreaded, asynchronous performance workload for measuring an achievable data transfer rate on an existing network setup.
For more information, see How to Use NTttcp to Test Network Performance in the Windows Dev Center.
When setting up NTttcp, consider the following:
A single thread should be sufficient for optimal throughput.
Multiple threads are required only for single-to-many clients.
Posting enough user receive buffers (by increasing the value passed to the -a option) reduces TCP copying.
You should not excessively post user receive buffers because the first buffers that are posted would return before you need to use other buffers.
It is best to bind each set of threads to a logical processor (the second delimited parameter in the -m option).
Each thread creates a logical processor that connects to (listens) a different port.
Table 8. Example Syntax for NTttcp Sender and Receiver
Syntax
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Details
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Example Syntax for a Sender
NTttcps –m 1,0,10.1.2.3 –a 2
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Single thread.
Bound to CPU 0.
Connects to a computer that uses IP 10.1.2.3.
Posts two send-overlapped buffers.
Default buffer size: 64 K.
Default number of buffers to send: 20 K.
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Example Syntax for a Receiver
NTttcpr –m 1,0,10.1.2.3 –a 6 –fr
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Single thread.
Bound to CPU 0.
Binds on local computer to IP 10.1.2.3.
Posts six receive-overlapped buffers.
Default buffer size: 64 KB.
Default number of buffers to receive: 20 K.
Posts full-length (64 K) receive buffers.
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Note Make sure that you enable all offloading features on the network adapter.
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