1/*******************************************************************************
2* Copyright 2017-2018 Intel Corporation
3*
4* Licensed under the Apache License, Version 2.0 (the "License");
5* you may not use this file except in compliance with the License.
6* You may obtain a copy of the License at
7*
8* http://www.apache.org/licenses/LICENSE-2.0
9*
10* Unless required by applicable law or agreed to in writing, software
11* distributed under the License is distributed on an "AS IS" BASIS,
12* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13* See the License for the specific language governing permissions and
14* limitations under the License.
15*******************************************************************************/
16
17#include "mkldnn_thread.hpp"
18#include "utils.hpp"
19
20#include "scratchpad.hpp"
21
22namespace mkldnn {
23namespace impl {
24
25/* Allocating memory buffers on a page boundary to reduce TLB/page misses */
26const size_t page_size = 2097152;
27
28/*
29 Implementation of the scratchpad_t interface that is compatible with
30 a concurrent execution
31*/
32struct concurent_scratchpad_t : public scratchpad_t {
33 concurent_scratchpad_t(size_t size) {
34 size_ = size;
35 scratchpad_ = (char *) malloc(size, page_size);
36 assert(scratchpad_ != nullptr);
37 }
38
39 ~concurent_scratchpad_t() {
40 free(scratchpad_);
41 }
42
43 virtual char *get() const {
44 return scratchpad_;
45 }
46
47private:
48 char *scratchpad_;
49 size_t size_;
50};
51
52/*
53 Implementation of the scratchpad_t interface that uses a global
54 scratchpad
55*/
56
57struct global_scratchpad_t : public scratchpad_t {
58 global_scratchpad_t(size_t size) {
59 if (size > size_) {
60 if (scratchpad_ != nullptr) free(scratchpad_);
61 size_ = size;
62 scratchpad_ = (char *) malloc(size, page_size);
63 assert(scratchpad_ != nullptr);
64 }
65 reference_count_++;
66 }
67
68 ~global_scratchpad_t() {
69 reference_count_--;
70 if (reference_count_ == 0) {
71 free(scratchpad_);
72 scratchpad_ = nullptr;
73 size_ = 0;
74 }
75 }
76
77 virtual char *get() const {
78 return scratchpad_;
79 }
80
81private:
82 /*
83 Using thread-local here is unnecessary and even buggy! All threads
84 actually share the same scratchpad, which is created and queried only
85 on the main thread. If the scratchpad is queried on some thread other
86 than the one it was created on (e.g. the application calls the API from
87 multiple threads), thread-local causes a segfault because the scratchpad
88 is uninitialized on the current thread.
89 */
90 /*thread_local*/ static char *scratchpad_;
91 /*thread_local*/ static size_t size_;
92 /*thread_local*/ static unsigned int reference_count_;
93};
94
95/*thread_local*/ char *global_scratchpad_t::scratchpad_ = nullptr;
96/*thread_local*/ size_t global_scratchpad_t::size_ = 0;
97/*thread_local*/ unsigned int global_scratchpad_t::reference_count_ = 0;
98
99
100/*
101 Scratchpad creation routine
102*/
103scratchpad_t *create_scratchpad(size_t size) {
104#ifndef MKLDNN_ENABLE_CONCURRENT_EXEC
105 return new global_scratchpad_t(size);
106#else
107 return new concurent_scratchpad_t(size);
108#endif
109}
110
111}
112}
113