Load Test Device¶
- Authors
Jonathan P. Newman
- IO
Frame Source, Register Access
- ONIX ID
27
- ONIX Hubs
This device is used for real-world bandwidth and latency testing.
Description¶
The Load Test device that produces data at user-settable size and rate to stress test various communication links and test closed-loop response latency.
Register Programming¶
Address |
Name |
Access |
Time of Effect |
POR Value |
Reset Action |
Description |
|---|---|---|---|---|---|---|
0x00 |
ENABLE |
R/W |
On Reset |
Implementation dependent, see hub documentation |
None |
The LSB is used to enable or disable the device data stream:
|
0x01 |
CLK_DIV |
R/W |
On Reset |
CLK_HZ / HB_HZ where HB_HZ is a implementation dependent default rate |
None |
Heartbeat clock divider ratio. Minimum value is CLK_HZ / 10e6 |
0x02 |
CLK_HZ |
R |
N/A |
N/A |
None |
The frequency parameter, CLK_HZ, used in the calculation of CLK_DIV. |
0x03 |
DT0H16_WORDS |
R/W |
On Reset |
0 |
None |
The number of incrementing 16-bit integers sent in each frame. Note The maximum value of DT0H16_WORDS depends of CLK_HZ and CLK_DIV. There needs to be enough clock cycles to satisfy
\[DT0H16\_WORDS <= CLK\_HZ / CLK\_DIV - 9\]
Setting DTOH16_WORDS above this value will result in a decreased device to host load as samples will be skipped. |
0x04 |
HTOD32_WORDS |
R/W |
On Reset |
0 |
None |
The number of 32-bit word dummy data in in each Host To Device frame. Write frames always start with a single 64-bit unsisigned integer, which is looped subtracted from the Hub Clock Counter when it is received to produce a Hub Clock Delta that is looped back into the device to host data frame for testing loop latency. All other data is ingored. |
Device To Host Data Frames¶
With DT0H16_WORDS = 4, each frame transmitted to the host is structured as follows:
- Hub Clock Counter Delta
64-bit unsigned integer that the result of subtracting the Hub Clock Counter value from the Hub Clock Counter Loop back value in Host To Device Data Frames. This provides a real-world, hardware timed measurement of closed-loop latency.
- Frame Word N
Ignored data that can be used for host to device load testing. When DT0H16_WORDS is set to a different value, the Data Size field along with the number of words at the end of the frame will change.
Host To Device Data Frames¶
With HTOD32_WORDS = 2, each frame transmitted to the host is structured as follows:
- Hub Clock Counter Loopback
64-bit unsigned integer that is subtracted from the current Hub Clock Counter value to produce the Hub Clock Counter Delta field in Device To Host Data Frames.
- Frame Word N
Ignored data that can be used for host to device load testing.