source: doc/theses/thierry_delisle_PhD/code/readyQ_proto/utils.hpp@ bb7422a

ADT ast-experimental
Last change on this file since bb7422a was 634a5c2, checked in by Thierry Delisle <tdelisle@…>, 4 years ago

New changes to the prototype with Andrew's comments

  • Property mode set to 100644
File size: 6.7 KB
Line 
1#pragma once
2
3#include <cassert>
4#include <cstddef>
5#include <atomic>
6#include <chrono>
7#include <fstream>
8#include <iostream>
9
10#include <unistd.h>
11#include <sys/sysinfo.h>
12
13// #include <x86intrin.h>
14
15// class Random {
16// private:
17// unsigned int seed;
18// public:
19// Random(int seed) {
20// this->seed = seed;
21// }
22
23// /** returns pseudorandom x satisfying 0 <= x < n. **/
24// unsigned int next() {
25// seed ^= seed << 6;
26// seed ^= seed >> 21;
27// seed ^= seed << 7;
28// return seed;
29// }
30// };
31
32constexpr uint64_t extendedEuclidY(uint64_t a, uint64_t b);
33constexpr uint64_t extendedEuclidX(uint64_t a, uint64_t b){
34 return (b==0) ? 1 : extendedEuclidY(b, a - b * (a / b));
35}
36constexpr uint64_t extendedEuclidY(uint64_t a, uint64_t b){
37 return (b==0) ? 0 : extendedEuclidX(b, a - b * (a / b)) - (a / b) * extendedEuclidY(b, a - b * (a / b));
38}
39
40class Random {
41private:
42 uint64_t x;
43
44 static constexpr const uint64_t M = 1ul << 48ul;
45 static constexpr const uint64_t A = 25214903917;
46 static constexpr const uint64_t C = 11;
47 static constexpr const uint64_t D = 16;
48
49public:
50 static constexpr const uint64_t m = M;
51 static constexpr const uint64_t a = A;
52 static constexpr const uint64_t c = C;
53 static constexpr const uint64_t d = D;
54 static constexpr const uint64_t ai = extendedEuclidX(A, M);
55public:
56 Random(unsigned int seed) {
57 this->x = seed * a;
58 }
59
60 /** returns pseudorandom x satisfying 0 <= x < n. **/
61 unsigned int next() {
62 //nextx = (a * x + c) % m;
63 x = (A * x + C) & (M - 1);
64 return x >> D;
65 }
66 unsigned int prev() {
67 //prevx = (ainverse * (x - c)) mod m
68 unsigned int r = x >> D;
69 x = ai * (x - C) & (M - 1);
70 return r;
71 }
72
73 void set_raw_state(uint64_t _x) {
74 this->x = _x;
75 }
76
77 uint64_t get_raw_state() {
78 return this->x;
79 }
80};
81
82static inline long long int rdtscl(void) {
83 #if defined( __i386 ) || defined( __x86_64 )
84 unsigned int lo, hi;
85 __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
86 return ( (unsigned long long)lo)|( ((unsigned long long)hi)<<32 );
87 #elif defined( __aarch64__ ) || defined( __arm__ )
88 // https://github.com/google/benchmark/blob/v1.1.0/src/cycleclock.h#L116
89 long long int virtual_timer_value;
90 asm volatile("mrs %0, cntvct_el0" : "=r"(virtual_timer_value));
91 return virtual_timer_value;
92 #else
93 #error unsupported hardware architecture
94 #endif
95}
96
97#if defined( __i386 ) || defined( __x86_64 )
98 #define Pause() __asm__ __volatile__ ( "pause" : : : )
99#elif defined( __ARM_ARCH )
100 #define Pause() __asm__ __volatile__ ( "YIELD" : : : )
101#else
102 #error unsupported architecture
103#endif
104
105static inline void affinity(int tid) {
106 static int cpus = get_nprocs();
107
108 cpu_set_t mask;
109 CPU_ZERO(&mask);
110 int cpu = cpus - tid; // Set CPU affinity to tid, starting from the end
111 CPU_SET(cpu, &mask);
112 auto result = sched_setaffinity(0, sizeof(mask), &mask);
113 if(result != 0) {
114 std::cerr << "Affinity set failed with " << result<< ", wanted " << cpu << std::endl;
115 }
116}
117
118static const constexpr std::size_t cache_line_size = 64;
119static inline void check_cache_line_size() {
120 std::cout << "Checking cache line size" << std::endl;
121 const std::string cache_file = "/sys/devices/system/cpu/cpu0/cache/index0/coherency_line_size";
122
123 std::ifstream ifs (cache_file, std::ifstream::in);
124
125 if(!ifs.good()) {
126 std::cerr << "Could not open file to check cache line size" << std::endl;
127 std::cerr << "Looking for: " << cache_file << std::endl;
128 std::exit(2);
129 }
130
131 size_t got;
132 ifs >> got;
133
134 ifs.close();
135
136 if(cache_line_size != got) {
137 std::cerr << "Cache line has incorrect size : " << got << std::endl;
138 std::exit(1);
139 }
140
141 std::cout << "Done" << std::endl;
142}
143
144using Clock = std::chrono::high_resolution_clock;
145using duration_t = std::chrono::duration<double>;
146using std::chrono::nanoseconds;
147
148template<typename Ratio, typename T>
149T duration_cast(T seconds) {
150 return std::chrono::duration_cast<std::chrono::duration<T, Ratio>>(std::chrono::duration<T>(seconds)).count();
151}
152
153static inline unsigned rand_bit(unsigned rnum, size_t mask) __attribute__((artificial));
154static inline unsigned rand_bit(unsigned rnum, size_t mask) {
155 unsigned bit = mask ? rnum % __builtin_popcountl(mask) : 0;
156#if !defined(__BMI2__)
157 uint64_t v = mask; // Input value to find position with rank r.
158 unsigned int r = bit + 1;// Input: bit's desired rank [1-64].
159 unsigned int s; // Output: Resulting position of bit with rank r [1-64]
160 uint64_t a, b, c, d; // Intermediate temporaries for bit count.
161 unsigned int t; // Bit count temporary.
162
163 // Do a normal parallel bit count for a 64-bit integer,
164 // but store all intermediate steps.
165 a = v - ((v >> 1) & ~0UL/3);
166 b = (a & ~0UL/5) + ((a >> 2) & ~0UL/5);
167 c = (b + (b >> 4)) & ~0UL/0x11;
168 d = (c + (c >> 8)) & ~0UL/0x101;
169
170
171 t = (d >> 32) + (d >> 48);
172 // Now do branchless select!
173 s = 64;
174 s -= ((t - r) & 256) >> 3; r -= (t & ((t - r) >> 8));
175 t = (d >> (s - 16)) & 0xff;
176 s -= ((t - r) & 256) >> 4; r -= (t & ((t - r) >> 8));
177 t = (c >> (s - 8)) & 0xf;
178 s -= ((t - r) & 256) >> 5; r -= (t & ((t - r) >> 8));
179 t = (b >> (s - 4)) & 0x7;
180 s -= ((t - r) & 256) >> 6; r -= (t & ((t - r) >> 8));
181 t = (a >> (s - 2)) & 0x3;
182 s -= ((t - r) & 256) >> 7; r -= (t & ((t - r) >> 8));
183 t = (v >> (s - 1)) & 0x1;
184 s -= ((t - r) & 256) >> 8;
185 return s - 1;
186#else
187 uint64_t picked = _pdep_u64(1ul << bit, mask);
188 return picked ? __builtin_ctzl(picked) : 0;
189#endif
190}
191
192// Barrier from
193class barrier_t {
194public:
195 barrier_t(size_t total)
196 : waiting(0)
197 , total(total)
198 {}
199
200 void wait(unsigned) {
201 size_t target = waiting++;
202 target = (target - (target % total)) + total;
203 while(waiting < target)
204 Pause();
205
206 assert(waiting < (1ul << 60));
207 }
208
209private:
210 std::atomic<size_t> waiting;
211 size_t total;
212};
213
214struct spinlock_t {
215 std::atomic_bool ll = { false };
216
217 inline void lock() {
218 while( __builtin_expect(ll.exchange(true),false) ) {
219 while(ll.load(std::memory_order_relaxed))
220 Pause();
221 }
222 }
223
224 inline bool try_lock() {
225 return false == ll.exchange(true);
226 }
227
228 inline void unlock() {
229 ll.store(false, std::memory_order_release);
230 }
231
232 inline explicit operator bool() {
233 return ll.load(std::memory_order_relaxed);
234 }
235};
236
237static inline bool bts(std::atomic_size_t & target, size_t bit ) {
238 //*
239 int result = 0;
240 asm volatile(
241 "LOCK btsq %[bit], %[target]\n\t"
242 :"=@ccc" (result)
243 : [target] "m" (target), [bit] "r" (bit)
244 );
245 return result != 0;
246 /*/
247 size_t mask = 1ul << bit;
248 size_t ret = target.fetch_or(mask, std::memory_order_relaxed);
249 return (ret & mask) != 0;
250 //*/
251}
252
253static inline bool btr(std::atomic_size_t & target, size_t bit ) {
254 //*
255 int result = 0;
256 asm volatile(
257 "LOCK btrq %[bit], %[target]\n\t"
258 :"=@ccc" (result)
259 : [target] "m" (target), [bit] "r" (bit)
260 );
261 return result != 0;
262 /*/
263 size_t mask = 1ul << bit;
264 size_t ret = target.fetch_and(~mask, std::memory_order_relaxed);
265 return (ret & mask) != 0;
266 //*/
267}
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