Intel IXP400 manual Code Size, IxAtmSch Data Memory Usage, Per VC Data Per Port Data Total

Intel® IXP400 Software

Access-Layer Components: ATM Transmit Scheduler (IxAtmSch) API

Some function interfaces supplied by the IXP400 software component adhere to structure requirements specified by the IxAtmdAcc component. However, no explicit dependency exists between the IxAtmSch component and the IxAtmdAcc component.

6.7Error Handling

IxAtmSch returns an error type to the user when the client is expected to handle the error. Internal errors will be reported using standard processor error-reporting techniques.

6.8Memory Requirements

Memory estimates have been sub-divided into two main areas: performance critical and not performance critical.

6.8.1Code Size

The ixAtmSch code size is approximately 35 Kbytes.

6.8.2Data Memory

There are a maximum of 32 VCs per port and eight ports supported by the IxAtmSch component. These multipliers are used in Table 10.

Table 10. IxAtmSch Data Memory Usage

	Per VC Data	Per Port Data	Total
Performance Critical Data	36	44 + (32 * 36) = 1,196	9,568
Non Critical Data	40	12 + (40 * 32) = 192	10,336
Total	76	2,488	19,904

6.9Performance

The key performance measure for the IxAtmSch component is the rate at which it can generate the schedule table, measured by time per cell. The rate at which queue updates are performed is also important. As this second situation will happen less frequently, however — because a great many cells may be queued in one call to the update function — it is of secondary importance.

The remaining functionality provided by the IxAtmSch is infrequent in nature, being used to initialize or modify the configuration of the component. This situation is not performance-critical as it does not affect the data path of the IXP42X product line processors.

Programmer’s Guide	IXP400 Software Version 2.0	April 2005
	Document Number: 252539, Revision: 007	85