This input specifies how many tokens are to be added to the bucket after each interval. A
token is equal to 1 byte. This value must be greater than 0. The value of this input
should not be changed when CTL_TX_RLIM_ENABLE is a value of 1.
This value should be calculated based on the desired rate and the value in
CTL_TX_RLIM_INTV.
Example: Programming the Rate Limiter
Assuming the following:
- Local bus clock frequency is 200 MHz
- BurstMax is 256 bytes
- Transmission rate is to be limited to 16 Gb/s (or 2 GB/s)
- Interval is arbitrarily chosen to be 16 Local bus clock cycles
The value for CTL_TX_RLIM_DELTA is:
- = (Byte Rate × Interval) / Local bus Frequency
- = (29 × 16) / (2006)
- = 160 bytes
The value for CTL_TX_RLIM_MAX must be BurstMax (typically 256B) or
greater. Different values result in different shaping of traffic. Simulations must be
done to select the proper value to get the desired packet rate.