Understanding the Display

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usb3testmain

The main USB3Test Application window is divided into 5 sections: Select USB test, Endpoint Type, Mode, Results & Control buttons.

The above diagram shows the Results Display following BOTH a successful Loopback test and a Benchmark test.

 

Main Window

The main screen contains the following options:

Device: This drop-down list shows each connected PassMark USB3 device (i.e. each port being tested). Each port will have an indication of whether the port is configured as super, high or full-speed. The relevant device should be selected for each test. If PassMark USB3 devices are added or removed while the application is running, or host controllers are added with loopback devices connected, the drop-down selection list will be automatically updated.

Test Mode: The Loopback function or benchmark function should be selected by selecting either Loopback or Benchmark.

Duration: Sets the duration of tests. Specified in minutes. Specifying ··means run the next test forever ·i.e. until manually stopped.

Loopback:

When a Loopback test is started, USB3Test will send a packet of data to the USB device, which will loop this data back in firmware and send the same data back to the PC. This is defined as 1 Loopback operation. This will be repeated until the test is stopped manually or the test duration is reached.

Benchmark:

Allows the data transfer rates for short bursts of data transfer to be measured. A Benchmark test can consist of a burst of data to the loopback device, a burst of data from the loopback device, a burst of data to the loopback device followed by a burst of data from the loopback device, and simultaneous bursts of data to and from the loopback device (depending on the type of the host controller). When a test started, USB3Test will transmit or wait to receive a block of data (as appropriate for the test type selected) and calculate the maximum speed based on the time to send of receive the expected blocks. This will be repeated until the test is stopped manually or the test duration is reached.

The USB3 firmware sends packets with pre-defined values to the PC.

The overall maximum, average and minimum of the read and write results are then displayed.

Note. Benchmark speeds may reduce as more USB devices are connected to the host on a USB port. This is dependent on many factors, but the main determinant is the type of the host port. USB 1.1 and 2.0 devices are in effect multidropped on the same bus, so that maximum speeds go down proportionately for each device on the bus. USB3.0 devices however, effectively have a single connection to each device, so in theory each device connected to a host port can operate at maximum speed. However, this just moves the bottleneck to the bus that connects the USB3.0 port to the host.

It is recommended that all other USB devices be disconnected from your PC when performing the benchmark test if you plan to obtain the maximum data rate.

Note 2: The USB 3.0 loopback plug will connect to the USB port at the highest possible speed, either Fullspeed (12Mb/s), Highspeed (480Mb/s). or Superspeed (5GMb/s).

 

Configuration Window

Various parameters may be configured for each test depending on mode, endpoint type and connection speed. The following options may appear in the configuration window.

In Endpoint No : This option allows the in endpoint number to be selected. The options may change depending on connection speed and endpoint type.

Out Endpoint No : This option allows the out endpoint number to be selected. The options may change depending on connection speed and endpoint type.

Endpoint Type : This option allows the endpoint type to be selected. Isochronous endpoint is only available in benchmark mode.

Burst Length : USB3.0 host controlleers and devices allow a burst of packets to be sent. This options defines the number of packets to be sent in a burst. This option will only appear when the host is a superspeed controller.

Loopback load : This option allows the data transfer load to be modified by inserting delays between each Write and Read cycle. It is only applicable to the loopback test.

Check bus errors : When this option is enabled, the loopback plug tests the port for low-level physical or link layer errors after every 1000 operations.

Benchmark Options : This option allows the direction of data transfers to be defined for the benchmark tests. On Superspeed devices, data transfers can be both inward and outward at the same time.

Usb transfer options : Different test data can be sent to the USB 3.0 loopback plug (this provides different types of reliability testing and alters the transfer speed).

Transfer Size: A transfer is a collection of USB packets. A greater number of packets per transfer reduces the USB overhead and helps achieve a higher data rate in the benchmark mode. Transfet size for the loopback mode is always 64 kilobytes.
Queue Size: This setting helps in initiating multiple transfers and adding them to the task queue. It reduces the latency between successive transfers. Therefore, queuing a greater number of transfers yields a higher data rate.
Constant·(i.e. the same) data will be sent all of the time. The constant value can be specified in the box next to the constant (default)·option. The default constant value is 0. This value may be in the range 0 to 255.
Incrementing sequence·means data will be sent in a data block  (i.e. the first byte will be as specified in data to transfer· the second byte will be Byte1 + 1, the third byte will be Byte2 + 1 etc. up to 0xFF (255) after which point the data will resume incrementing from 0.
Random numbers·means a random pattern of data will be sent in the data block.
Verify data transferred: Specifies (i) that during a Loopback test the data sent to the PassMark USB3 device matches the data received (ii) the predefined Benchmark data expected from the PassMark USB3 device is correct.

 

Results

The USB3Test results are contained in 3 sections: Title bar, test summary and a benchmark graph result.

Results heading: Displays two lines:

(i)The name of the USB 3.0 loopback plug under test and the current status of the test.
(ii)The duration of the test, the number of operations performed in the current test and the number of errors detected based on the ?erify data transferred·setting described above.

Test summary: Displays a textual summary of the tests as they occur.

This summary starts with a list of the PassMark USB devices connected to USB ports. Specifically, this includes the:

-The Version of USB3Test.
-USB3.0 Loopback plug identifier (e.g. PMUSB-0). The device number is allocated by the device driver, typically based on the order that the devices are plugged in. Hence, these numbers are not fixed.
-The USB port speed mode (i.e. FullSpeed, HighSpeed,SuperSpeed ) that the USB3Test plug has been able to enumerate at.
-USB3.0 Loopback plug programmed serial number. This is fixed. It may be useful when using more than 1 USB3.0 Loopback plug to identify which plug and hence port is to be tested.

Loopback test results show the number of:

-Operations.
-Verification errors: Verification errors are based on the USB3Test software detecting that the data sent is not the same as the data received. This is a serious error.
-Device transceiver errors. Device transceiver errors are triggered when the USB transceiver on the USB 3.0 loopback plug detects what it considers to be an error. These are events at a low level that may lead to the packet being retransmitted. They do not represent data errors at the application level. These errors are normally not visible to the user, but are displayed to help identify potential problems, for example, poor quality cables, cables that are too long, or system internals with insufficient electrical shielding with high electrical interference on the bus.  Errors that may cause a device transceiver error are:
Bad PID
CRC error
Bit stuff error
Extra bits in a packet
Full Speed EOP ending on K
Loss of high-speed valid before EOP (truncated packet)
Overflow (host clock running too fast or device clock running too slow)
Token larger than 3 bytes

It should be noted that device transceiver errors are not an indication that the USB port does not comply with the USB Specification.

 

Benchmark results show the Maximum rate for reading and writing over the USB port (i.e. the Maximum reading and writing speed measured by the USB3.0 Loopback plug). The average and minimum transfer rates are also displayed.

The current test results (i.e. since the last Reset All·may be viewed by sliding the scroll bar on the right hand side of the results section).

Benchmark graph: Displays the overall maximum USB rate measured over the port that the current test device is connected. Below this value, a graph displays 2 column bars, the left-hand bar shows the maximum read rate and the right-hand bar shows the maximum write rate (in Mb/s). Both bars are color coded with the following meaning:

Red ·Just about stopped (poor)
Yellow ound a mid-range gear (mediocre)
Green ·Full steam ahead (excellent)

 

Control buttons

The Control buttons are at the bottom right of the main window.

Start: Starts a test based on the settings described above.

Stop: Stops a test.

Configure: Displays the configuration window.

Flash LEDs: To verify that the LEDs are working, Flash LEDs switches all LEDs off for 0.5 seconds, and then switches all LEDs on for 0.5 seconds. The LEDs will then return to their initial state.

Reset All: Refreshes the list of available plugs.

Save Log: Allows a test Summary·to be saved to a file. Up to the last 3000 logged lines are saved.

About: Displays information about this software.

Help: Provides on-line help.

Exit: Closes this software.