The trace buffer is 128kB. The amount of instructions it can hold depends on the mode of the trace buffer. In PSoC Designer versions up to 3.21 there are three available modes for the trace buffer: PC only, PC/Registers, and PC/Timestamp. The number of instructions contained in the trace buffer depends on the trace mode selected.
In "PC only" trace mode, each line of the trace buffer contains only the 2 bytes of the program counter. This means that 65,536 instructions are contained in the trace buffer. In "PC/Registers" and "PC/Timestamp," each line of the trace buffer contains 8 bytes of information. This means that the buffer contains 16,384 instructions.