Kernel Bypass - 2024.1 English

AI Engine-ML Kernel and Graph Programming Guide (UG1603)

Document ID
UG1603
Release Date
2024-06-06
Version
2024.1 English

A bypass encapsulator construct is used to execute a kernel conditionally. The control of the bypass is done through a runtime parameter.

The bypass runtime control input bp : 0 for no bypass and 1 for bypass. In addition to the control parameter, the external connections of a bypassed kernel or a graph are directed to the external ports of the bypass construct itself. Internally, the bypass construct is connected to the bypassed kernel or the graph automatically by the compiler.

The negate modifier can be used to denote that the input control is negated. By default, the control is synchronous RTP. To use asynchronous RTP, use the async modifier.

The following example shows the required coding.

input_port control;
input_port in;
output_port out;
bypass b;
kernel k;
k = kernel::create(filter);
dimensions(k.in[0])={32};
dimensions(k.out[0])={32};
...
b = bypass::create(k);
connect<parameter> (control, async(negate(b.bp)));
connect(in, b.in[0]);
connect(b.out[0], out);
Note: For the bypass to work correctly, a one-to-one correspondence between the input and output buffer ports is required, both in type and size.