dsp_K data sheet

for AD-2106x SHARC

15 October, 2000

Copyright Notice

This document is part of the dsp_K source distribution and a licensed DSP_K DESCRIPTION document. The figures in this data sheet are obtained on an AD-21065L "SHARC" DSP simulator, with an external clock at 30Mhz, doubled to 60MHz internal core. While effort has been made to be accurate, the figures are approximations only. The dsp_K API software is fully described in a companion technical note.

version

The figures refer to the snapshot we call kernel version 0.6. The kernel BSP is fully described in the programer guide.

Runtime measures

The times given here are measurements taken from test programs and are representative of real kernel overhead. The columns show figures for program data residing both on-chip and off-chip data with zero external memory wait states. The code is compiled with debugging enabled and with no optimisation.

measure	kernel functions	clock cycles (time) internal	clock cycles (time) external (0 wait states)
context switch (new task)	_DSP_K_SWITCH	180(3uS) programmatic 300(5uS) unravel interrupt 240(4uS) average	270(4uS) average
context switch (same task)	_DSP_K_SWITCH	35(<1uS)	40(<1uS)
task schedule	DSP_K_TASK_SCHEDULE priority scheduler	75(1uS)	85(1uS)
task pend	MONOLITH_TASK_PEND	25(<1uS)	30(<1uS)
task ready	MONOLITH_TASK_READY	30(<1uS)	35(<1uS)
semaphore give (non-block)	MONOLITH_SEMA_GIVE	75(1uS)	80(1uS)
semaphore take (non-block)	MONOLITH_SEMA_TAKE	60(1uS)	65(1uS)
message send (unblock)	MONOLITH_MSG_SEND	230(4uS)	250(4uS)
message receive (block)	MONOLITH_MSG_RECEIVE	140(2uS)	155(2uS)
channel output (blocking)	PROCESS_OUT	80(1uS)	90(<2uS)
channel input (non-blocking)	PROCESS_IN	100(<2uS)	110(<2uS)
interrupt latency (into ISR)	fast wrapper	55(<1uS)	60(1uS)
interrupt exit (ISR to code)	fast wrapper	20(<1uS)	25(<1uS)
driver open	MONOLITH_DRVR_OPEN	40(<1uS)	45(<1uS)
driver read	MONOLITH_DRVR_READ	50(<1uS)	55(<1uS)
driver write	MONOLITH_DRVR_WRITE	50(<1uS)	55(<1uS)
driver close	MONOLITH_DRVR_CLOSE	40(<1uS)	45(<1uS)

Build measures

The table below shows the build sizes (code and data) as indicated.

Tasks	ITCs	Drivers	Pcode	Data
4	5	1	0xc77	0xd8

The sizes shown don't include task stacks, which have to be user allocated. The kernel relies on C library support which has to be present to support user tasks, and this needs a further 0x20e program words and 0x2ac data words. The exact figures for an application can be found by producing a memory map output from the VDSP linker options.