1530e1a690
This patch models a simple HMC Controller. It simply schedules the incoming packets to HMC Serial Links using a round robin mechanism. This patch should be applied in series with other patches modeling a complete HMC device. Committed by: Nilay Vaish <nilay@cs.wisc.edu>
74 lines
3.7 KiB
Python
74 lines
3.7 KiB
Python
# Copyright (c) 2012-2013 ARM Limited
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# All rights reserved.
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#
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# The license below extends only to copyright in the software and shall
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# not be construed as granting a license to any other intellectual
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# property including but not limited to intellectual property relating
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# to a hardware implementation of the functionality of the software
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# licensed hereunder. You may use the software subject to the license
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# terms below provided that you ensure that this notice is replicated
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# unmodified and in its entirety in all distributions of the software,
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# modified or unmodified, in source code or in binary form.
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#
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# Copyright (c) 2015 The University of Bologna
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met: redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer;
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# redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution;
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# neither the name of the copyright holders nor the names of its
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# contributors may be used to endorse or promote products derived from
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# this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#
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# Authors: Erfan Azarkhish
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from m5.params import *
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from XBar import *
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# References:
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# [1] http://www.open-silicon.com/open-silicon-ips/hmc/
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# [2] Ahn, J.; Yoo, S.; Choi, K., "Low-Power Hybrid Memory Cubes With Link
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# Power Management and Two-Level Prefetching," TVLSI 2015
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# The HMCController class highlights the fact that a component is required
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# between host and HMC to convert the host protocol (AXI for example) to the
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# serial links protocol. Moreover, this component should have large internal
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# queueing to hide the access latency of the HMC.
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# Plus, this controller can implement more advanced global scheduling policies
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# and can reorder and steer transactions if required. A good example of such
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# component is available in [1].
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# Also in [2] there is a similar component which is connected to all serial
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# links, and it schedules the requests to the ones which are not busy.
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# These two references clarify two things:
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# 1. The serial links support the same address range and packets can travel
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# over any of them.
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# 2. One host can be connected to more than 1 serial link simply to achieve
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# higher bandwidth, and not for any other reason.
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# In this model, we have used a round-robin counter, because it is the
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# simplest way to schedule packets over the non-busy serial links. However,
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# more advanced scheduling algorithms are possible and even host can dedicate
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# each serial link to a portion of the address space and interleave packets
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# over them. Yet in this model, we have not made any such assumptions on the
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# address space.
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class HMCController(NoncoherentXBar):
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type = 'HMCController'
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cxx_header = "mem/hmc_controller.hh"
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