src/cpu/minor/pipeline.cc - public/gem5 - Git at Google

 /*
  * Copyright (c) 2013-2014, 2020 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
  * not be construed as granting a license to any other intellectual
  * property including but not limited to intellectual property relating
  * to a hardware implementation of the functionality of the software
  * licensed hereunder.  You may use the software subject to the license
  * terms below provided that you ensure that this notice is replicated
  * unmodified and in its entirety in all distributions of the software,
  * modified or unmodified, in source code or in binary form.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met: redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer;
  * redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in the
  * documentation and/or other materials provided with the distribution;
  * neither the name of the copyright holders nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "cpu/minor/pipeline.hh"

 #include <algorithm>

 #include "cpu/minor/decode.hh"
 #include "cpu/minor/execute.hh"
 #include "cpu/minor/fetch1.hh"
 #include "cpu/minor/fetch2.hh"
 #include "debug/Drain.hh"
 #include "debug/MinorCPU.hh"
 #include "debug/MinorTrace.hh"
 #include "debug/Quiesce.hh"

 namespace gem5
 {

 GEM5_DEPRECATED_NAMESPACE(Minor, minor);
 namespace minor
 {

 Pipeline::Pipeline(MinorCPU &cpu_, const MinorCPUParams &params) :
     Ticked(cpu_, &(cpu_.BaseCPU::baseStats.numCycles)),
     cpu(cpu_),
     allow_idling(params.enableIdling),
     f1ToF2(cpu.name() + ".f1ToF2", "lines",
         params.fetch1ToFetch2ForwardDelay),
     f2ToF1(cpu.name() + ".f2ToF1", "prediction",
         params.fetch1ToFetch2BackwardDelay, true),
     f2ToD(cpu.name() + ".f2ToD", "insts",
         params.fetch2ToDecodeForwardDelay),
     dToE(cpu.name() + ".dToE", "insts",
         params.decodeToExecuteForwardDelay),
     eToF1(cpu.name() + ".eToF1", "branch",
         params.executeBranchDelay),
     execute(cpu.name() + ".execute", cpu, params,
         dToE.output(), eToF1.input()),
     decode(cpu.name() + ".decode", cpu, params,
         f2ToD.output(), dToE.input(), execute.inputBuffer),
     fetch2(cpu.name() + ".fetch2", cpu, params,
         f1ToF2.output(), eToF1.output(), f2ToF1.input(), f2ToD.input(),
         decode.inputBuffer),
     fetch1(cpu.name() + ".fetch1", cpu, params,
         eToF1.output(), f1ToF2.input(), f2ToF1.output(), fetch2.inputBuffer),
     activityRecorder(cpu.name() + ".activity", Num_StageId,
         /* The max depth of inter-stage FIFOs */
         std::max(params.fetch1ToFetch2ForwardDelay,
         std::max(params.fetch2ToDecodeForwardDelay,
         std::max(params.decodeToExecuteForwardDelay,
         params.executeBranchDelay)))),
     needToSignalDrained(false)
 {
     if (params.fetch1ToFetch2ForwardDelay < 1) {
         fatal("%s: fetch1ToFetch2ForwardDelay must be >= 1 (%d)\n",
             cpu.name(), params.fetch1ToFetch2ForwardDelay);
     }

     if (params.fetch2ToDecodeForwardDelay < 1) {
         fatal("%s: fetch2ToDecodeForwardDelay must be >= 1 (%d)\n",
             cpu.name(), params.fetch2ToDecodeForwardDelay);
     }

     if (params.decodeToExecuteForwardDelay < 1) {
         fatal("%s: decodeToExecuteForwardDelay must be >= 1 (%d)\n",
             cpu.name(), params.decodeToExecuteForwardDelay);
     }

     if (params.executeBranchDelay < 1) {
         fatal("%s: executeBranchDelay must be >= 1\n",
             cpu.name(), params.executeBranchDelay);
     }
 }

 void
 Pipeline::minorTrace() const
 {
     fetch1.minorTrace();
     f1ToF2.minorTrace();
     f2ToF1.minorTrace();
     fetch2.minorTrace();
     f2ToD.minorTrace();
     decode.minorTrace();
     dToE.minorTrace();
     execute.minorTrace();
     eToF1.minorTrace();
     activityRecorder.minorTrace();
 }

 void
 Pipeline::evaluate()
 {
     /** We tick the CPU to update the BaseCPU cycle counters */
     cpu.tick();

     /* Note that it's important to evaluate the stages in order to allow
      *  'immediate', 0-time-offset TimeBuffer activity to be visible from
      *  later stages to earlier ones in the same cycle */
     execute.evaluate();
     decode.evaluate();
     fetch2.evaluate();
     fetch1.evaluate();

     if (debug::MinorTrace)
         minorTrace();

     /* Update the time buffers after the stages */
     f1ToF2.evaluate();
     f2ToF1.evaluate();
     f2ToD.evaluate();
     dToE.evaluate();
     eToF1.evaluate();

     /* The activity recorder must be be called after all the stages and
      *  before the idler (which acts on the advice of the activity recorder */
     activityRecorder.evaluate();

     if (allow_idling) {
         /* Become idle if we can but are not draining */
         if (!activityRecorder.active() && !needToSignalDrained) {
             DPRINTF(Quiesce, "Suspending as the processor is idle\n");
             stop();
         }

         /* Deactivate all stages.  Note that the stages *could*
          *  activate and deactivate themselves but that's fraught
          *  with additional difficulty.
          *  As organised herre */
         activityRecorder.deactivateStage(Pipeline::CPUStageId);
         activityRecorder.deactivateStage(Pipeline::Fetch1StageId);
         activityRecorder.deactivateStage(Pipeline::Fetch2StageId);
         activityRecorder.deactivateStage(Pipeline::DecodeStageId);
         activityRecorder.deactivateStage(Pipeline::ExecuteStageId);
     }

     if (needToSignalDrained) /* Must be draining */
     {
         DPRINTF(Drain, "Still draining\n");
         if (isDrained()) {
             DPRINTF(Drain, "Signalling end of draining\n");
             cpu.signalDrainDone();
             needToSignalDrained = false;
             stop();
         }
     }
 }

 MinorCPU::MinorCPUPort &
 Pipeline::getInstPort()
 {
     return fetch1.getIcachePort();
 }

 MinorCPU::MinorCPUPort &
 Pipeline::getDataPort()
 {
     return execute.getDcachePort();
 }

 void
 Pipeline::wakeupFetch(ThreadID tid)
 {
     fetch1.wakeupFetch(tid);
 }

 bool
 Pipeline::drain()
 {
     DPRINTF(MinorCPU, "Draining pipeline by halting inst fetches. "
         " Execution should drain naturally\n");

     execute.drain();

     /* Make sure that needToSignalDrained isn't accidentally set if we
      *  are 'pre-drained' */
     bool drained = isDrained();
     needToSignalDrained = !drained;

     return drained;
 }

 void
 Pipeline::drainResume()
 {
     DPRINTF(Drain, "Drain resume\n");

     for (ThreadID tid = 0; tid < cpu.numThreads; tid++) {
         fetch1.wakeupFetch(tid);
     }

     execute.drainResume();
 }

 bool
 Pipeline::isDrained()
 {
     bool fetch1_drained = fetch1.isDrained();
     bool fetch2_drained = fetch2.isDrained();
     bool decode_drained = decode.isDrained();
     bool execute_drained = execute.isDrained();

     bool f1_to_f2_drained = f1ToF2.empty();
     bool f2_to_f1_drained = f2ToF1.empty();
     bool f2_to_d_drained = f2ToD.empty();
     bool d_to_e_drained = dToE.empty();

     bool ret = fetch1_drained && fetch2_drained &&
         decode_drained && execute_drained &&
         f1_to_f2_drained && f2_to_f1_drained &&
         f2_to_d_drained && d_to_e_drained;

     DPRINTF(MinorCPU, "Pipeline undrained stages state:%s%s%s%s%s%s%s%s\n",
         (fetch1_drained ? "" : " Fetch1"),
         (fetch2_drained ? "" : " Fetch2"),
         (decode_drained ? "" : " Decode"),
         (execute_drained ? "" : " Execute"),
         (f1_to_f2_drained ? "" : " F1->F2"),
         (f2_to_f1_drained ? "" : " F2->F1"),
         (f2_to_d_drained ? "" : " F2->D"),
         (d_to_e_drained ? "" : " D->E")
         );

     return ret;
 }

 } // namespace minor
 } // namespace gem5
	/*
	* Copyright (c) 2013-2014, 2020 ARM Limited
	* All rights reserved
	*
	* The license below extends only to copyright in the software and shall
	* not be construed as granting a license to any other intellectual
	* property including but not limited to intellectual property relating
	* to a hardware implementation of the functionality of the software
	* licensed hereunder. You may use the software subject to the license
	* terms below provided that you ensure that this notice is replicated
	* unmodified and in its entirety in all distributions of the software,
	* modified or unmodified, in source code or in binary form.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met: redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer;
	* redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution;
	* neither the name of the copyright holders nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "cpu/minor/pipeline.hh"

	#include <algorithm>

	#include "cpu/minor/decode.hh"
	#include "cpu/minor/execute.hh"
	#include "cpu/minor/fetch1.hh"
	#include "cpu/minor/fetch2.hh"
	#include "debug/Drain.hh"
	#include "debug/MinorCPU.hh"
	#include "debug/MinorTrace.hh"
	#include "debug/Quiesce.hh"

	namespace gem5
	{

	GEM5_DEPRECATED_NAMESPACE(Minor, minor);
	namespace minor
	{

	Pipeline::Pipeline(MinorCPU &cpu_, const MinorCPUParams &params) :
	Ticked(cpu_, &(cpu_.BaseCPU::baseStats.numCycles)),
	cpu(cpu_),
	allow_idling(params.enableIdling),
	f1ToF2(cpu.name() + ".f1ToF2", "lines",
	params.fetch1ToFetch2ForwardDelay),
	f2ToF1(cpu.name() + ".f2ToF1", "prediction",
	params.fetch1ToFetch2BackwardDelay, true),
	f2ToD(cpu.name() + ".f2ToD", "insts",
	params.fetch2ToDecodeForwardDelay),
	dToE(cpu.name() + ".dToE", "insts",
	params.decodeToExecuteForwardDelay),
	eToF1(cpu.name() + ".eToF1", "branch",
	params.executeBranchDelay),
	execute(cpu.name() + ".execute", cpu, params,
	dToE.output(), eToF1.input()),
	decode(cpu.name() + ".decode", cpu, params,
	f2ToD.output(), dToE.input(), execute.inputBuffer),
	fetch2(cpu.name() + ".fetch2", cpu, params,
	f1ToF2.output(), eToF1.output(), f2ToF1.input(), f2ToD.input(),
	decode.inputBuffer),
	fetch1(cpu.name() + ".fetch1", cpu, params,
	eToF1.output(), f1ToF2.input(), f2ToF1.output(), fetch2.inputBuffer),
	activityRecorder(cpu.name() + ".activity", Num_StageId,
	/* The max depth of inter-stage FIFOs */
	std::max(params.fetch1ToFetch2ForwardDelay,
	std::max(params.fetch2ToDecodeForwardDelay,
	std::max(params.decodeToExecuteForwardDelay,
	params.executeBranchDelay)))),
	needToSignalDrained(false)
	{
	if (params.fetch1ToFetch2ForwardDelay < 1) {
	fatal("%s: fetch1ToFetch2ForwardDelay must be >= 1 (%d)\n",
	cpu.name(), params.fetch1ToFetch2ForwardDelay);
	}

	if (params.fetch2ToDecodeForwardDelay < 1) {
	fatal("%s: fetch2ToDecodeForwardDelay must be >= 1 (%d)\n",
	cpu.name(), params.fetch2ToDecodeForwardDelay);
	}

	if (params.decodeToExecuteForwardDelay < 1) {
	fatal("%s: decodeToExecuteForwardDelay must be >= 1 (%d)\n",
	cpu.name(), params.decodeToExecuteForwardDelay);
	}

	if (params.executeBranchDelay < 1) {
	fatal("%s: executeBranchDelay must be >= 1\n",
	cpu.name(), params.executeBranchDelay);
	}
	}

	void
	Pipeline::minorTrace() const
	{
	fetch1.minorTrace();
	f1ToF2.minorTrace();
	f2ToF1.minorTrace();
	fetch2.minorTrace();
	f2ToD.minorTrace();
	decode.minorTrace();
	dToE.minorTrace();
	execute.minorTrace();
	eToF1.minorTrace();
	activityRecorder.minorTrace();
	}

	void
	Pipeline::evaluate()
	{
	/** We tick the CPU to update the BaseCPU cycle counters */
	cpu.tick();

	/* Note that it's important to evaluate the stages in order to allow
	* 'immediate', 0-time-offset TimeBuffer activity to be visible from
	* later stages to earlier ones in the same cycle */
	execute.evaluate();
	decode.evaluate();
	fetch2.evaluate();
	fetch1.evaluate();

	if (debug::MinorTrace)
	minorTrace();

	/* Update the time buffers after the stages */
	f1ToF2.evaluate();
	f2ToF1.evaluate();
	f2ToD.evaluate();
	dToE.evaluate();
	eToF1.evaluate();

	/* The activity recorder must be be called after all the stages and
	* before the idler (which acts on the advice of the activity recorder */
	activityRecorder.evaluate();

	if (allow_idling) {
	/* Become idle if we can but are not draining */
	if (!activityRecorder.active() && !needToSignalDrained) {
	DPRINTF(Quiesce, "Suspending as the processor is idle\n");
	stop();
	}

	/* Deactivate all stages. Note that the stages could
	* activate and deactivate themselves but that's fraught
	* with additional difficulty.
	* As organised herre */
	activityRecorder.deactivateStage(Pipeline::CPUStageId);
	activityRecorder.deactivateStage(Pipeline::Fetch1StageId);
	activityRecorder.deactivateStage(Pipeline::Fetch2StageId);
	activityRecorder.deactivateStage(Pipeline::DecodeStageId);
	activityRecorder.deactivateStage(Pipeline::ExecuteStageId);
	}

	if (needToSignalDrained) /* Must be draining */
	{
	DPRINTF(Drain, "Still draining\n");
	if (isDrained()) {
	DPRINTF(Drain, "Signalling end of draining\n");
	cpu.signalDrainDone();
	needToSignalDrained = false;
	stop();
	}
	}
	}

	MinorCPU::MinorCPUPort &
	Pipeline::getInstPort()
	{
	return fetch1.getIcachePort();
	}

	MinorCPU::MinorCPUPort &
	Pipeline::getDataPort()
	{
	return execute.getDcachePort();
	}

	void
	Pipeline::wakeupFetch(ThreadID tid)
	{
	fetch1.wakeupFetch(tid);
	}

	bool
	Pipeline::drain()
	{
	DPRINTF(MinorCPU, "Draining pipeline by halting inst fetches. "
	" Execution should drain naturally\n");

	execute.drain();

	/* Make sure that needToSignalDrained isn't accidentally set if we
	* are 'pre-drained' */
	bool drained = isDrained();
	needToSignalDrained = !drained;

	return drained;
	}

	void
	Pipeline::drainResume()
	{
	DPRINTF(Drain, "Drain resume\n");

	for (ThreadID tid = 0; tid < cpu.numThreads; tid++) {
	fetch1.wakeupFetch(tid);
	}

	execute.drainResume();
	}

	bool
	Pipeline::isDrained()
	{
	bool fetch1_drained = fetch1.isDrained();
	bool fetch2_drained = fetch2.isDrained();
	bool decode_drained = decode.isDrained();
	bool execute_drained = execute.isDrained();

	bool f1_to_f2_drained = f1ToF2.empty();
	bool f2_to_f1_drained = f2ToF1.empty();
	bool f2_to_d_drained = f2ToD.empty();
	bool d_to_e_drained = dToE.empty();

	bool ret = fetch1_drained && fetch2_drained &&
	decode_drained && execute_drained &&
	f1_to_f2_drained && f2_to_f1_drained &&
	f2_to_d_drained && d_to_e_drained;

	DPRINTF(MinorCPU, "Pipeline undrained stages state:%s%s%s%s%s%s%s%s\n",
	(fetch1_drained ? "" : " Fetch1"),
	(fetch2_drained ? "" : " Fetch2"),
	(decode_drained ? "" : " Decode"),
	(execute_drained ? "" : " Execute"),
	(f1_to_f2_drained ? "" : " F1->F2"),
	(f2_to_f1_drained ? "" : " F2->F1"),
	(f2_to_d_drained ? "" : " F2->D"),
	(d_to_e_drained ? "" : " D->E")
	);

	return ret;
	}

	} // namespace minor
	} // namespace gem5