From 27378ecbe40ea037c30f6790bfdc424ed64442b4 Mon Sep 17 00:00:00 2001 From: Giacomo Travaglini Date: Fri, 1 Mar 2019 13:56:59 +0000 Subject: [PATCH] Revert "cpu: fix how a thread starts up in MinorCPU" This reverts commit 02dafc5498750d9734ba8f2a1608a846f90b71d1. The commit was part of a patchset which broke MinorCPU regressions (switcheroo) Change-Id: I0a8098fc71abe5838014e587dbe372b258d8aa9f Signed-off-by: Giacomo Travaglini Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18604 Maintainer: Jason Lowe-Power Tested-by: kokoro --- src/cpu/minor/cpu.cc | 46 ++++++++++----------------------------- src/cpu/minor/cpu.hh | 10 --------- src/cpu/minor/execute.cc | 3 +-- src/cpu/minor/fetch2.cc | 1 - src/cpu/minor/fetch2.hh | 9 ++++---- src/cpu/minor/pipeline.cc | 1 - 6 files changed, 16 insertions(+), 54 deletions(-) diff --git a/src/cpu/minor/cpu.cc b/src/cpu/minor/cpu.cc index 484457bd4..63efde2dc 100644 --- a/src/cpu/minor/cpu.cc +++ b/src/cpu/minor/cpu.cc @@ -49,7 +49,6 @@ MinorCPU::MinorCPU(MinorCPUParams *params) : BaseCPU(params), - pipelineStartupEvent([this]{ wakeupPipeline(); }, name()), threadPolicy(params->threadPolicy) { /* This is only written for one thread at the moment */ @@ -280,43 +279,20 @@ MinorCPU::takeOverFrom(BaseCPU *old_cpu) void MinorCPU::activateContext(ThreadID thread_id) { - /* Remember to wake up this thread_id by scheduling the - * pipelineStartup event. - * We can't wakeupFetch the thread right away because its context may - * not have been fully initialized. For example, in the case of clone - * syscall, this activateContext function is called in the middle of - * the syscall and before the new thread context is initialized. - * If we start fetching right away, the new thread will fetch from an - * invalid address (i.e., pc is not initialized yet), which could lead - * to a page fault. Instead, we remember which threads to wake up and - * schedule an event to wake all them up after their contexts are - * fully initialized */ - readyThreads.push_back(thread_id); - if (!pipelineStartupEvent.scheduled()) - schedule(pipelineStartupEvent, clockEdge(Cycles(0))); -} - -void -MinorCPU::wakeupPipeline() -{ - for (auto thread_id : readyThreads) { - DPRINTF(MinorCPU, "ActivateContext thread: %d\n", thread_id); + DPRINTF(MinorCPU, "ActivateContext thread: %d\n", thread_id); - /* Do some cycle accounting. lastStopped is reset to stop the - * wakeup call on the pipeline from adding the quiesce period - * to BaseCPU::numCycles */ - stats.quiesceCycles += pipeline->cyclesSinceLastStopped(); - pipeline->resetLastStopped(); - - /* Wake up the thread, wakeup the pipeline tick */ - threads[thread_id]->activate(); - wakeupOnEvent(Minor::Pipeline::CPUStageId); + /* Do some cycle accounting. lastStopped is reset to stop the + * wakeup call on the pipeline from adding the quiesce period + * to BaseCPU::numCycles */ + stats.quiesceCycles += pipeline->cyclesSinceLastStopped(); + pipeline->resetLastStopped(); - pipeline->wakeupFetch(thread_id); - BaseCPU::activateContext(thread_id); - } + /* Wake up the thread, wakeup the pipeline tick */ + threads[thread_id]->activate(); + wakeupOnEvent(Minor::Pipeline::CPUStageId); + pipeline->wakeupFetch(thread_id); - readyThreads.clear(); + BaseCPU::activateContext(thread_id); } void diff --git a/src/cpu/minor/cpu.hh b/src/cpu/minor/cpu.hh index 606a401b6..4e4762390 100644 --- a/src/cpu/minor/cpu.hh +++ b/src/cpu/minor/cpu.hh @@ -83,13 +83,6 @@ class MinorCPU : public BaseCPU * Elements of pipeline call TheISA to implement the model. */ Minor::Pipeline *pipeline; - /** An event that wakes up the pipeline when a thread context is - * activated */ - EventFunctionWrapper pipelineStartupEvent; - - /** List of threads that are ready to wake up and run */ - std::vector readyThreads; - public: /** Activity recording for pipeline. This belongs to Pipeline but * stages will access it through the CPU as the MinorCPU object @@ -172,9 +165,6 @@ class MinorCPU : public BaseCPU void activateContext(ThreadID thread_id) override; void suspendContext(ThreadID thread_id) override; - /** Wake up ready-to-run threads */ - void wakeupPipeline(); - /** Thread scheduling utility functions */ std::vector roundRobinPriority(ThreadID priority) { diff --git a/src/cpu/minor/execute.cc b/src/cpu/minor/execute.cc index 81d310bba..810ff11c6 100644 --- a/src/cpu/minor/execute.cc +++ b/src/cpu/minor/execute.cc @@ -1061,8 +1061,7 @@ Execute::commit(ThreadID thread_id, bool only_commit_microops, bool discard, !branch.isStreamChange() && /* No real branch */ fault == NoFault && /* No faults */ completed_inst && /* Still finding instructions to execute */ - num_insts_committed != commitLimit && /* Not reached commit limit */ - cpu.getContext(thread_id)->status() != ThreadContext::Suspended + num_insts_committed != commitLimit /* Not reached commit limit */ ) { if (only_commit_microops) { diff --git a/src/cpu/minor/fetch2.cc b/src/cpu/minor/fetch2.cc index b374ee9bf..d60a1bab0 100644 --- a/src/cpu/minor/fetch2.cc +++ b/src/cpu/minor/fetch2.cc @@ -120,7 +120,6 @@ Fetch2::dumpAllInput(ThreadID tid) popInput(tid); fetchInfo[tid].inputIndex = 0; - fetchInfo[tid].havePC = false; } void diff --git a/src/cpu/minor/fetch2.hh b/src/cpu/minor/fetch2.hh index 114dec0f5..ecd6a81ec 100644 --- a/src/cpu/minor/fetch2.hh +++ b/src/cpu/minor/fetch2.hh @@ -173,11 +173,6 @@ class Fetch2 : public Named Stats::Scalar storeInstructions; Stats::Scalar amoInstructions; - public: - /** Dump the whole contents of the input buffer. Useful after a - * prediction changes control flow */ - void dumpAllInput(ThreadID tid); - protected: /** Get a piece of data to work on from the inputBuffer, or 0 if there * is no data. */ @@ -186,6 +181,10 @@ class Fetch2 : public Named /** Pop an element off the input buffer, if there are any */ void popInput(ThreadID tid); + /** Dump the whole contents of the input buffer. Useful after a + * prediction changes control flow */ + void dumpAllInput(ThreadID tid); + /** Update local branch prediction structures from feedback from * Execute. */ void updateBranchPrediction(const BranchData &branch); diff --git a/src/cpu/minor/pipeline.cc b/src/cpu/minor/pipeline.cc index 3248d5465..b5659ac0d 100644 --- a/src/cpu/minor/pipeline.cc +++ b/src/cpu/minor/pipeline.cc @@ -199,7 +199,6 @@ void Pipeline::wakeupFetch(ThreadID tid) { fetch1.wakeupFetch(tid); - fetch2.dumpAllInput(tid); } bool -- 2.30.2