1 | // |
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2 | // Cforall Version 1.0.0 Copyright (C) 2022 University of Waterloo |
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3 | // |
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4 | // The contents of this file are covered under the licence agreement in the |
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5 | // file "LICENCE" distributed with Cforall. |
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6 | // |
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7 | // cluster.hfa -- file that includes helpers for subsystem that need cluster wide support |
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8 | // |
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9 | // Author : Thierry Delisle |
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10 | // Created On : Tue Mar 15 16:40:12 2022 |
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11 | // Last Modified By : |
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12 | // Last Modified On : |
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13 | // Update Count : |
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14 | // |
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15 | |
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16 | #pragma once |
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17 | |
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18 | #include "device/cpu.hfa" |
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19 | #include "kernel/private.hfa" |
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20 | |
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21 | #include <limits.h> |
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22 | |
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23 | //----------------------------------------------------------------------- |
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24 | // Calc moving average based on existing average, before and current time. |
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25 | static inline unsigned long long moving_average(unsigned long long currtsc, unsigned long long instsc, unsigned long long old_avg) { |
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26 | /* paranoid */ verifyf( old_avg < 15000000000000, "Suspiciously large previous average: %'llu (%llx)\n", old_avg, old_avg ); |
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27 | |
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28 | const unsigned long long new_val = currtsc > instsc ? currtsc - instsc : 0; |
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29 | const unsigned long long total_weight = 16; |
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30 | const unsigned long long new_weight = 4; |
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31 | const unsigned long long old_weight = total_weight - new_weight; |
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32 | const unsigned long long ret = ((new_weight * new_val) + (old_weight * old_avg)) / total_weight; |
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33 | return ret; |
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34 | } |
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35 | |
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36 | static inline void touch_tsc(__timestamp_t * tscs, size_t idx, unsigned long long ts_prev, unsigned long long ts_next) { |
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37 | if (ts_next == ULLONG_MAX) return; |
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38 | unsigned long long now = rdtscl(); |
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39 | unsigned long long pma = __atomic_load_n(&tscs[ idx ].t.ma, __ATOMIC_RELAXED); |
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40 | __atomic_store_n(&tscs[ idx ].t.tv, ts_next, __ATOMIC_RELAXED); |
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41 | __atomic_store_n(&tscs[ idx ].t.ma, moving_average(now, ts_prev, pma), __ATOMIC_RELAXED); |
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42 | } |
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43 | |
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44 | //----------------------------------------------------------------------- |
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45 | // Calc age a timestamp should be before needing help. |
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46 | forall(Data_t * | { unsigned long long ts(Data_t & this); }) |
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47 | static inline unsigned long long calc_cutoff( |
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48 | const unsigned long long ctsc, |
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49 | unsigned procid, |
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50 | size_t count, |
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51 | Data_t * data, |
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52 | __timestamp_t * tscs, |
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53 | const unsigned shard_factor |
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54 | ) { |
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55 | unsigned start = procid; |
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56 | unsigned long long max = 0; |
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57 | for(i; shard_factor) { |
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58 | unsigned long long ptsc = ts(data[start + i]); |
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59 | if(ptsc != ULLONG_MAX) { |
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60 | /* paranoid */ verify( start + i < count ); |
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61 | unsigned long long tsc = moving_average(ctsc, ptsc, tscs[start + i].t.ma); |
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62 | if(tsc > max) max = tsc; |
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63 | } |
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64 | } |
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65 | return (max + 2 * max) / 2; |
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66 | } |
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67 | |
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68 | static inline unsigned cache_id(struct cluster * cltr, unsigned idx) with (cltr->sched) { |
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69 | // Figure out the current cpu and make sure it is valid |
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70 | const int cpu = __kernel_getcpu(); |
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71 | /* paranoid */ verify(cpu >= 0); |
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72 | /* paranoid */ verify(cpu < cpu_info.hthrd_count); |
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73 | unsigned this_cache = cpu_info.llc_map[cpu].cache; |
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74 | |
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75 | // Super important: don't write the same value over and over again |
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76 | // We want to maximise our chances that his particular values stays in cache |
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77 | if(caches[idx].id != this_cache) |
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78 | __atomic_store_n(&caches[idx].id, this_cache, __ATOMIC_RELAXED); |
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79 | |
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80 | return this_cache; |
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81 | } |
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82 | |
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83 | static struct { |
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84 | const unsigned readyq; |
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85 | const unsigned io; |
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86 | } __shard_factor = { 2, 1 }; |
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87 | |
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88 | // Local Variables: // |
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89 | // mode: c // |
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90 | // tab-width: 4 // |
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91 | // End: // |
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