21 Feb
2012
21 Feb
'12
2:46 a.m.
On Tue, 21 Feb 2012, Alexey Toptygin wrote:
Date: Tue, 21 Feb 2012 02:19:23 +0000 (UTC)
From: Alexey Toptygin <alexeyt at freeshell.org>
Reply-To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
Subject: Re: non-x86 multicore - Re: CPU monoculture
On Mon, 20 Feb 2012, Peter C. Wallace wrote:
I just fits in the continuum of computing devices ranked by latency/parallism
you might also choose a GA or XMOS device for ease of programming relative to
a FPGA, I think most people would say that XMOS and GA devices are easier than
FPGAs to program (or at least use more familiar tools)
FPGAs,etc lowest latency greatest parallelism, core local I/O
XMOS/GA medium latency medium parallelism, core local I/O
DSPs medium/high latency, little/medium parallelism, shared I/O path
GP CPUs high latency/ medium parallelism, shared I/O path
Peter Wallace
It all has to do with real time and latency. X86s
(and their assosciated
chipsets) have great throughput but dreadful latency (this is a common
tradeoff) especially for hardware replacement type tasks. The XMOS chips
have low latency (ns) and independent I/O available on multiple cores, the
X86 cores share a (high latency/buffered) common data path
As I said before, the XMOS chips are designed for multiple coupled tasks
with (somewhat in FPGA space if the signal frequencies are not above
perhaps a few 10 of MHz). It is designed to simulate hardware in software.
The x86 cannot do this very well, so as I said simply does not play in the
same space at all.
So, if I undestand you correctly, the point of the XCore/GA style technology
is to do in software what would be done in a more traditional design with
FPGA/PAL/ASIC based circuits? So the advantage of XCore/GA is rapid
prototyping and flexibility of implementation?
Alexey