| [708ae38] | 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 | #include "kernel/private.hfa"
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| 17 |
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| 18 | //-----------------------------------------------------------------------
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| 19 | // Calc moving average based on existing average, before and current time.
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| 20 | static inline unsigned long long moving_average(unsigned long long currtsc, unsigned long long instsc, unsigned long long old_avg) {
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| 21 | /* paranoid */ verifyf( currtsc < 45000000000000000, "Suspiciously large current time: %'llu (%llx)\n", currtsc, currtsc );
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| 22 | /* paranoid */ verifyf( instsc < 45000000000000000, "Suspiciously large insert time: %'llu (%llx)\n", instsc, instsc );
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| 23 | /* paranoid */ verifyf( old_avg < 15000000000000, "Suspiciously large previous average: %'llu (%llx)\n", old_avg, old_avg );
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| 24 |
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| 25 | const unsigned long long new_val = currtsc > instsc ? currtsc - instsc : 0;
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| 26 | const unsigned long long total_weight = 16;
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| 27 | const unsigned long long new_weight = 4;
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| 28 | const unsigned long long old_weight = total_weight - new_weight;
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| 29 | const unsigned long long ret = ((new_weight * new_val) + (old_weight * old_avg)) / total_weight;
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| 30 | return ret;
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| 31 | }
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| 32 |
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| 33 | //-----------------------------------------------------------------------
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| 34 | // Calc age a timestamp should be before needing help.
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| 35 | forall(Data_t * | { unsigned long long ts(Data_t & this); })
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| 36 | static inline unsigned long long calc_cutoff(
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| 37 | const unsigned long long ctsc,
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| 38 | const processor * proc,
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| 39 | size_t count,
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| 40 | Data_t * data,
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| 41 | __timestamp_t * tscs,
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| 42 | const unsigned shard_factor
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| 43 | ) {
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| 44 | unsigned start = proc->rdq.id;
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| 45 | unsigned long long max = 0;
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| 46 | for(i; shard_factor) {
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| 47 | unsigned long long ptsc = ts(data[start + i]);
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| 48 | if(ptsc != -1ull) {
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| 49 | /* paranoid */ verify( start + i < count );
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| 50 | unsigned long long tsc = moving_average(ctsc, ptsc, tscs[start + i].ma);
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| 51 | if(tsc > max) max = tsc;
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| 52 | }
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| 53 | }
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| 54 | return (max + 2 * max) / 2;
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| 55 | }
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| 56 |
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| 57 | static inline unsigned cache_id(struct cluster * cltr, unsigned idx) with (cltr->sched) {
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| 58 | // Figure out the current cpu and make sure it is valid
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| 59 | const int cpu = __kernel_getcpu();
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| 60 | /* paranoid */ verify(cpu >= 0);
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| 61 | /* paranoid */ verify(cpu < cpu_info.hthrd_count);
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| 62 | unsigned this_cache = cpu_info.llc_map[cpu].cache;
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| 63 |
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| 64 | // Super important: don't write the same value over and over again
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| 65 | // We want to maximise our chances that his particular values stays in cache
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| 66 | if(caches[idx].id != this_cache)
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| 67 | __atomic_store_n(&caches[idx].id, this_cache, __ATOMIC_RELAXED);
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| 68 |
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| 69 | return this_cache;
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| 70 | }
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| 71 |
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| 72 | static struct {
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| 73 | const unsigned readyq;
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| 74 | } __shard_factor = { 2 };
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| 75 |
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| 76 | // Local Variables: //
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| 77 | // mode: c //
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| 78 | // tab-width: 4 //
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| 79 | // End: //
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