[a552a8c] | 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 | // comp_fair.cfa -- Test that spinning doesn't cause completions to get stuck. |
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| 8 | // This test should work without io_uring but isn't very useful without |
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| 9 | // |
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| 10 | // Author : Thierry Delisle |
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| 11 | // Created On : Thu Mar 10 15:06:50 2022 |
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| 12 | // Last Modified By : |
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| 13 | // Last Modified On : |
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| 14 | // Update Count : |
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| 15 | // |
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| 16 | |
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| 17 | |
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[1417f6b] | 18 | #include <concurrency/barrier.hfa> |
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[a552a8c] | 19 | #include <fstream.hfa> |
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| 20 | #include <iofwd.hfa> |
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| 21 | #include <kernel.hfa> |
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| 22 | #include <thread.hfa> |
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| 23 | |
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| 24 | #include <errno.h> |
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| 25 | #include <string.h> |
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| 26 | #include <unistd.h> |
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| 27 | |
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| 28 | struct { |
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[680137a] | 29 | barrier & bar; |
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| 30 | int pipe[2]; |
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[a552a8c] | 31 | |
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| 32 | } globals; |
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| 33 | |
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| 34 | Duration default_preemption() { |
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| 35 | return 0; |
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| 36 | } |
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| 37 | |
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| 38 | enum { TIMES = 1000 }; |
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| 39 | |
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| 40 | volatile unsigned counter = 0; |
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| 41 | |
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| 42 | |
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| 43 | // ----- Spinner ----- |
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| 44 | // spins trying to prevent other threads from getting to this processor |
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| 45 | thread Spinner {}; |
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| 46 | void main(Spinner &) { |
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| 47 | unsigned last = 0; |
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| 48 | for() { |
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| 49 | unsigned curr = __atomic_load_n(&counter, __ATOMIC_SEQ_CST); |
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| 50 | |
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[72ba508] | 51 | if(curr >= TIMES) break; |
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[a552a8c] | 52 | |
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| 53 | if(last == curr) { |
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| 54 | Pause(); |
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| 55 | continue; |
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| 56 | } |
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| 57 | |
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| 58 | last = curr; |
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| 59 | yield(); |
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| 60 | } |
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| 61 | } |
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| 62 | |
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| 63 | // ----- Reader ----- |
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| 64 | // Reader from the pipe to test completion doesn't starve |
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| 65 | thread Reader {}; |
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| 66 | void main(Reader & this) { |
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[69698d2] | 67 | char thrash[1]; |
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[680137a] | 68 | bool do_read = has_user_level_blocking( (fptr_t)async_read ); |
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| 69 | |
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| 70 | for(TIMES) { |
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| 71 | io_future_t f; |
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| 72 | if ( do_read ) { |
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| 73 | async_read(f, globals.pipe[0], thrash, 1, 0); |
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| 74 | } else { |
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| 75 | fulfil(f, 0); // If we don't have user-level blocking just play along |
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| 76 | } |
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[a552a8c] | 77 | |
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[680137a] | 78 | block( globals.bar ); |
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[1417f6b] | 79 | |
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[d2ad151] | 80 | yield( (unsigned)prng( this, 15 ) ); |
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[a552a8c] | 81 | |
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[680137a] | 82 | unsigned i = __atomic_add_fetch( &counter, 1, __ATOMIC_SEQ_CST ); |
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[a552a8c] | 83 | if(0 == (i % 100)) sout | i; |
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| 84 | |
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[680137a] | 85 | wait( f ); |
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[a552a8c] | 86 | |
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[680137a] | 87 | if(f.result < 0) |
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| 88 | abort | "Read error" | -f.result | ":" | strerror(-f.result); |
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[a552a8c] | 89 | |
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[680137a] | 90 | block( globals.bar ); |
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| 91 | } |
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[a552a8c] | 92 | } |
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| 93 | |
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| 94 | // ----- Writer ----- |
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| 95 | // Writes to the pipe so the Reader can unblock |
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| 96 | // takes its sweet time so the Reader has to block |
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| 97 | thread Writer {}; |
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| 98 | void main(Writer & this) { |
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[680137a] | 99 | for(TIMES) { |
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| 100 | block( globals.bar ); |
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[a552a8c] | 101 | |
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[680137a] | 102 | sleep( 1`us ); |
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[a552a8c] | 103 | |
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[680137a] | 104 | char buf[1] = { '+' }; |
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| 105 | int ret = write( globals.pipe[1], buf, 1 ); |
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| 106 | if(ret < 0) |
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| 107 | abort | "Write error" | errno | ":" | strerror(errno); |
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[a552a8c] | 108 | |
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[680137a] | 109 | block( globals.bar ); |
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| 110 | } |
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[a552a8c] | 111 | } |
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| 112 | |
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| 113 | // ----- Yielder ----- |
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| 114 | // Add some chaos into the mix |
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| 115 | thread Yielder {}; |
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| 116 | void ^?{}(Yielder &mutex ) {} |
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| 117 | void main(Yielder&) { |
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| 118 | while(TIMES > __atomic_load_n(&counter, __ATOMIC_SEQ_CST)) { |
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| 119 | yield(); |
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| 120 | } |
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| 121 | } |
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| 122 | |
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| 123 | int main() { |
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[680137a] | 124 | barrier bar = { 2 }; |
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| 125 | &globals.bar = &bar; |
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| 126 | int ret = pipe(globals.pipe); |
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| 127 | if(ret != 0) |
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| 128 | abort | "Pipe error" | errno | ":" | strerror(errno); |
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[a552a8c] | 129 | |
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| 130 | processor p; |
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| 131 | sout | "starting"; |
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| 132 | { |
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| 133 | Yielder y; |
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| 134 | Spinner s; |
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| 135 | Reader ior; |
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[680137a] | 136 | Writer iow; |
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[a552a8c] | 137 | } |
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| 138 | sout | "done"; |
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[d2ad151] | 139 | } |
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