global_memory_pipeline.hh revision 11693:bc1f702c25b9 
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 contributors
18 * may be used to endorse or promote products derived from this software
19 * 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 * Author: John Kalamatianos, Sooraj Puthoor
34 */
35
36#ifndef __GLOBAL_MEMORY_PIPELINE_HH__
37#define __GLOBAL_MEMORY_PIPELINE_HH__
38
39#include <queue>
40#include <string>
41
42#include "gpu-compute/misc.hh"
43#include "params/ComputeUnit.hh"
44#include "sim/stats.hh"
45
46/*
47 * @file global_memory_pipeline.hh
48 *
49 * The global memory pipeline issues newly created global memory packets
50 * from the pipeline to DTLB. The exec() method of the memory packet issues
51 * the packet to the DTLB if there is space available in the return fifo.
52 * This stage also retires previously issued loads and stores that have
53 * returned from the memory sub-system.
54 */
55
56class ComputeUnit;
57
58class GlobalMemPipeline
59{
60  public:
61    GlobalMemPipeline(const ComputeUnitParams *params);
62    void init(ComputeUnit *cu);
63    void exec();
64
65    std::queue<GPUDynInstPtr> &getGMReqFIFO() { return gmIssuedRequests; }
66    std::queue<GPUDynInstPtr> &getGMStRespFIFO() { return gmReturnedStores; }
67    std::queue<GPUDynInstPtr> &getGMLdRespFIFO() { return gmReturnedLoads; }
68
69    bool
70    isGMLdRespFIFOWrRdy() const
71    {
72        return gmReturnedLoads.size() < gmQueueSize;
73    }
74
75    bool
76    isGMStRespFIFOWrRdy() const
77    {
78        return gmReturnedStores.size() < gmQueueSize;
79    }
80
81    bool
82    isGMReqFIFOWrRdy(uint32_t pendReqs=0) const
83    {
84        return (gmIssuedRequests.size() + pendReqs) < gmQueueSize;
85    }
86
87    const std::string &name() const { return _name; }
88    void regStats();
89
90    void
91    incLoadVRFBankConflictCycles(int num_cycles)
92    {
93        loadVrfBankConflictCycles += num_cycles;
94    }
95
96  private:
97    ComputeUnit *computeUnit;
98    std::string _name;
99    int gmQueueSize;
100
101    // number of cycles of delaying the update of a VGPR that is the
102    // target of a load instruction (or the load component of an atomic)
103    // The delay is due to VRF bank conflicts
104    Stats::Scalar loadVrfBankConflictCycles;
105    // Counters to track the inflight loads and stores
106    // so that we can provide the proper backpressure
107    // on the number of inflight memory operations.
108    int inflightStores;
109    int inflightLoads;
110
111    // The size of global memory.
112    int globalMemSize;
113
114    // Global Memory Request FIFO: all global memory requests
115    // are issued to this FIFO from the memory pipelines
116    std::queue<GPUDynInstPtr> gmIssuedRequests;
117
118    // Globa Store Response FIFO: all responses of global memory
119    // stores are sent to this FIFO from TCP
120    std::queue<GPUDynInstPtr> gmReturnedStores;
121
122    // Global Load Response FIFO: all responses of global memory
123    // loads are sent to this FIFO from TCP
124    std::queue<GPUDynInstPtr> gmReturnedLoads;
125};
126
127#endif // __GLOBAL_MEMORY_PIPELINE_HH__
128