1/*
2 * Copyright (c) 2014-2015 Advanced Micro Devices, Inc.
3 * All rights reserved.
4 *
5 * For use for simulation and test purposes only
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright notice,
14 * this list of conditions and the following disclaimer in the documentation
15 * and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the copyright holder nor the names of its
18 * contributors may be used to endorse or promote products derived from this
19 * software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 *
33 * Authors: Sooraj Puthoor
34 */
35
36#include "gpu-compute/local_memory_pipeline.hh"
37
38#include "debug/GPUPort.hh"
39#include "gpu-compute/compute_unit.hh"
40#include "gpu-compute/gpu_dyn_inst.hh"
41#include "gpu-compute/shader.hh"
42#include "gpu-compute/vector_register_file.hh"
43#include "gpu-compute/wavefront.hh"
44
45LocalMemPipeline::LocalMemPipeline(const ComputeUnitParams* p) :
46    computeUnit(nullptr), lmQueueSize(p->local_mem_queue_size)
47{
48}
49
50void
51LocalMemPipeline::init(ComputeUnit *cu)
52{
53    computeUnit = cu;
54    _name = computeUnit->name() + ".LocalMemPipeline";
55}
56
57void
58LocalMemPipeline::exec()
59{
60    // apply any returned shared (LDS) memory operations
61    GPUDynInstPtr m = !lmReturnedRequests.empty() ?
62        lmReturnedRequests.front() : nullptr;
63
64    bool accessVrf = true;
65    Wavefront *w = nullptr;
66
67    if ((m) && (m->isLoad() || m->isAtomicRet())) {
68        w = m->wavefront();
69
70        accessVrf =
71            w->computeUnit->vrf[w->simdId]->
72            vrfOperandAccessReady(m->seqNum(), w, m,
73                                  VrfAccessType::WRITE);
74    }
75
76    if (!lmReturnedRequests.empty() && m->latency.rdy() && accessVrf &&
77        computeUnit->locMemToVrfBus.rdy() && (computeUnit->shader->coissue_return
78                 || computeUnit->wfWait.at(m->pipeId).rdy())) {
79
80        lmReturnedRequests.pop();
81        w = m->wavefront();
82
83        m->completeAcc(m);
84
85        // Decrement outstanding request count
86        computeUnit->shader->ScheduleAdd(&w->outstandingReqs, m->time, -1);
87
88        if (m->isStore() || m->isAtomic()) {
89            computeUnit->shader->ScheduleAdd(&w->outstandingReqsWrLm,
90                                             m->time, -1);
91        }
92
93        if (m->isLoad() || m->isAtomic()) {
94            computeUnit->shader->ScheduleAdd(&w->outstandingReqsRdLm,
95                                             m->time, -1);
96        }
97
98        // Mark write bus busy for appropriate amount of time
99        computeUnit->locMemToVrfBus.set(m->time);
100        if (computeUnit->shader->coissue_return == 0)
101            w->computeUnit->wfWait.at(m->pipeId).set(m->time);
102    }
103
104    // If pipeline has executed a local memory instruction
105    // execute local memory packet and issue the packets
106    // to LDS
107    if (!lmIssuedRequests.empty() && lmReturnedRequests.size() < lmQueueSize) {
108
109        GPUDynInstPtr m = lmIssuedRequests.front();
110
111        bool returnVal = computeUnit->sendToLds(m);
112        if (!returnVal) {
113            DPRINTF(GPUPort, "packet was nack'd and put in retry queue");
114        }
115        lmIssuedRequests.pop();
116    }
117}
118
119void
120LocalMemPipeline::regStats()
121{
122    loadVrfBankConflictCycles
123        .name(name() + ".load_vrf_bank_conflict_cycles")
124        .desc("total number of cycles LDS data are delayed before updating "
125              "the VRF")
126        ;
127}
128