Myles Watson wrote:
I assume that you are talking about the XBAR buffer allocation, 4.6.12?
Sorry. I should have been more clear. I was talking about 3.3.15: LDTi Buffer Count Registers. Does your answer still apply?
I am looking at the public BKDG Publication # 32559 Revision: 3.08 draft Issue Date: July 2007.
The LDTi buffers(4.3.15) are part of the XBAR buffers (4.6.10).
"4.3.15 LDTi Buffer Count Registers These registers specify the number of command and data buffers for each virtual channel available for use by the transmitter at the other end of the specific HyperTransport™ technology link. See “XBAR Flow Control Buffers” on page 156 for more information on command and data buffers. Note: The reset values for each of the LDTn Buffer Count registers depend on the link connection type (coherent HyperTransport or noncoherent HyperTransport technology). Because hardware attempts to choose optimal settings, this register should not, in general, need to be changed."
Now that there is an open-source HT core from the University of Mannheim, anyone could do this, but maybe most people will leave it alone.
The core should still be profiled by the designers and recommended values documented by them. If none are given than I would assume that it is optimized to work with the default settings.
Marc