| 1 | //
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2021 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 | // topology.cfa -- read the data structure
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| 8 | //
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| 9 | // Author : Thierry Delisle
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| 10 | // Created On : Thu Jun 10 16:13:07 2021
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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 "device/cpu.hfa"
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| 17 |
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| 18 | #include <math.hfa>
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| 19 | #include <stdlib.hfa>
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| 20 |
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| 21 | #include <errno.h>
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| 22 | #include <stdio.h>
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| 23 | #include <string.h>
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| 24 | #include <unistd.h>
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| 25 |
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| 26 | extern "C" {
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| 27 | #include <dirent.h>
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| 28 | #include <sys/types.h>
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| 29 | #include <sys/stat.h>
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| 30 | #include <fcntl.h>
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| 31 | }
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| 32 |
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| 33 | // search a string for character 'character' but looking atmost at len
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| 34 | // chars
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| 35 | static const char * strnchr(const char * str, int character, size_t len) {
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| 36 | return (const char *)memchr(str, character, strnlen(str, len));
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| 37 | }
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| 38 |
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| 39 | // Check if have string matches the want string
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| 40 | // ignoring any characters that are longer than the want string
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| 41 | static bool strmatch(const char * want, char * have) {
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| 42 | size_t w = strlen(want);
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| 43 | return strncmp(want, have, w) == 0;
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| 44 | }
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| 45 |
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| 46 | typedef const char * idx_range_t;
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| 47 |
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| 48 | // read the value of a string and evaluate it
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| 49 | // get the end pointer and make sure it is all evaluated
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| 50 | static unsigned read_value(idx_range_t map, size_t len, const char ** end) {
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| 51 | unsigned long val = strtoul(map, (char**)end, 10);
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| 52 | /* paranoid */ __attribute__((unused)) size_t read = (*end - map);
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| 53 | /* paranoid */ verifyf(read <= len, "String '%s' passed with inconsistent length %zu", map, len);
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| 54 | /* paranoid */ verifyf(read == len, "String %.*s not entirely a number, %zu chars left", (int)len, map, len - read);
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| 55 | return val;
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| 56 | }
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| 57 |
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| 58 | // Evaluate the width of a comma seperated list of idx
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| 59 | // for example 'A-B,C-D,E,F' has a width of '(B-A) + (D-C) + 1 + 1'
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| 60 | // Also has an (non-optional) end ptr like strtoul and friends
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| 61 | //
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| 62 | // FIXME : the current implementation only supports 1 comma
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| 63 | static unsigned read_width(idx_range_t map, size_t len, const char ** end) {
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| 64 | // Do we have a comma
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| 65 | const char * comma = strnchr(map, ',', len);
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| 66 | if(comma != 0p) {
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| 67 | // We do! recurse and sum the widths
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| 68 | const char * _;
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| 69 | size_t split = comma - map;
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| 70 | unsigned lhs = read_width(map, split, &_);
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| 71 | unsigned rhs = read_width(comma + 1, len - split - 1, end);
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| 72 | return lhs + rhs;
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| 73 | }
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| 74 |
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| 75 | // No commas, check for a range
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| 76 | const char * dash = strnchr(map, '-', len);
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| 77 | if(dash != 0p) {
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| 78 | const char * _;
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| 79 | size_t split = dash - map;
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| 80 | unsigned lhs = read_value(map, split, &_);
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| 81 | unsigned rhs = read_value(dash + 1, len - split - 1, end);
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| 82 | return rhs - lhs + 1;
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| 83 | }
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| 84 |
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| 85 | // No range, no comma, just a single value
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| 86 | // It's width is 1 and we can consume everything
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| 87 | /* paranoid */ verifyf( ({strtoul(map, (char**)end, 10); *end == (map + len); }), "Value in range '%.*s' not a number", (int)len, map);
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| 88 | *end = map + len;
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| 89 | return 1;
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| 90 | }
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| 91 |
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| 92 | // go through a directory calling fn on each file
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| 93 | static int iterate_dir( const char * path, void (*fn)(struct dirent * ent) ) {
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| 94 | // open the directory
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| 95 | DIR *dir = opendir(path);
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| 96 | if(dir == 0p) { return ENOTDIR; }
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| 97 |
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| 98 | // call fn for each
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| 99 | struct dirent * ent;
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| 100 | while ((ent = readdir(dir)) != 0p) {
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| 101 | fn( ent );
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| 102 | }
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| 103 |
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| 104 | // no longer need this
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| 105 | closedir(dir);
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| 106 | return 0;
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| 107 | }
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| 108 |
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| 109 | // count the number of directories with the specified prefix
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| 110 | // the directories counted have the form '[prefix]N' where prefix is the parameter
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| 111 | // and N is an base 10 integer.
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| 112 | static int count_prefix_dirs(const char * path, const char * prefix) {
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| 113 | // read the directory and find the cpu count
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| 114 | // and make sure everything is as expected
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| 115 | int max = -1;
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| 116 | int count = 0;
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| 117 | void lambda(struct dirent * ent) {
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| 118 | // were are looking for prefixX, where X is a number
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| 119 | // check that it starts with 'cpu
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| 120 | char * s = strstr(ent->d_name, prefix);
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| 121 | if(s == 0p) { return; }
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| 122 | if(s != ent->d_name) { return; }
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| 123 |
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| 124 | // check that the next part is a number
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| 125 | s += strlen(prefix);
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| 126 | char * end;
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| 127 | long int val = strtol(s, &end, 10);
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| 128 | if(*end != '\0' || val < 0) { return; }
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| 129 |
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| 130 | // check that it's a directory
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| 131 | if(ent->d_type != DT_DIR) { return; }
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| 132 |
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| 133 | // it's a match!
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| 134 | max = max(val, max);
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| 135 | count++;
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| 136 | }
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| 137 | iterate_dir(path, lambda);
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| 138 |
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| 139 | /* paranoid */ verifyf(count == max + 1, "Inconsistent %s count, counted %d, but max %s was %d", prefix, count, prefix, (int)max);
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| 140 |
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| 141 | return count;
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| 142 | }
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| 143 |
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| 144 | // Count number of cpus in the system
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| 145 | static int count_cpus(void) {
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| 146 | const char * fpath = "/sys/devices/system/cpu/present";
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| 147 | int fd = open(fpath, 0, O_RDONLY);
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| 148 | /* paranoid */ verifyf(fd >= 0, "Could not open file %s", fpath);
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| 149 |
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| 150 | char buff[128];
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| 151 | ssize_t r = read(fd, buff, 128);
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| 152 | /* paranoid */ verifyf(r > 0, "Could not read file %s", fpath);
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| 153 | /* paranoid */ verify( buff[r-1] == '\n' );
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| 154 | buff[r-1] = '\0';
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| 155 |
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| 156 | /* paranoid */ __attribute__((unused)) int ret =
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| 157 | close(fd);
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| 158 | /* paranoid */ verifyf(ret == 0, "Could not close file %s", fpath);
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| 159 |
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| 160 | const char * _;
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| 161 | int cnt = read_width(buff, r - 1, &_);
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| 162 | /* paranoid */ verify(cnt == count_prefix_dirs("/sys/devices/system/cpu", "cpu"));
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| 163 | return cnt;
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| 164 | }
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| 165 |
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| 166 | // Count number of cache *indexes* in the system
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| 167 | // cache indexes are distinct from cache level as Data or Instruction cache
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| 168 | // can share a level but not an index
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| 169 | // PITFALL: assumes all cpus have the same indexes as cpu0
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| 170 | static int count_cache_indexes(void) {
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| 171 | return count_prefix_dirs("/sys/devices/system/cpu/cpu0/cache", "index");
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| 172 | }
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| 173 |
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| 174 |
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| 175 | // read information about a spcficic cache index/cpu file into the output buffer
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| 176 | static size_t read_cpuidxinfo_into(unsigned cpu, unsigned idx, const char * file, char * out, size_t out_len) {
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| 177 | // Pick the file we want and read it
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| 178 | char buf[128];
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| 179 | /* paranoid */ __attribute__((unused)) int len =
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| 180 | snprintf(buf, 128, "/sys/devices/system/cpu/cpu%u/cache/index%u/%s", cpu, idx, file);
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| 181 | /* paranoid */ verifyf(len > 0, "Could not generate '%s' filename for cpu %u, index %u", file, cpu, idx);
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| 182 |
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| 183 | int fd = open(buf, 0, O_RDONLY);
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| 184 | /* paranoid */ verifyf(fd > 0, "Could not open file '%s'", buf);
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| 185 |
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| 186 | ssize_t r = read(fd, out, out_len);
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| 187 | /* paranoid */ verifyf(r > 0, "Could not read file '%s'", buf);
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| 188 |
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| 189 | /* paranoid */ __attribute__((unused)) int ret =
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| 190 | close(fd);
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| 191 | /* paranoid */ verifyf(ret == 0, "Could not close file '%s'", buf);
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| 192 | return r;
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| 193 | }
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| 194 |
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| 195 | // Iterate over the cache indexes of a given cpu
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| 196 | typedef void (*handle_func_t)(unsigned idx, unsigned char level, idx_range_t range, size_t len);
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| 197 | static void foreach_cacheidx(unsigned cpu, unsigned idxs, handle_func_t handle) {
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| 198 | for(i; idxs) {
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| 199 | unsigned idx = idxs - 1 - i;
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| 200 | char buf[32];
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| 201 |
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| 202 | // Type says what kind of cache this is,
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| 203 | // Options are: Unified, Data, Instruction
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| 204 | read_cpuidxinfo_into(cpu, idx, "type", buf, 32);
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| 205 | if((!strmatch("Unified", buf)) && (!strmatch("Data", buf))) {
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| 206 | // We don't care about instruction caches
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| 207 | continue;
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| 208 | }
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| 209 |
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| 210 | // Level is the cache level: higher means bigger and slower
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| 211 | read_cpuidxinfo_into(cpu, idx, "level", buf, 32);
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| 212 | char * end;
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| 213 | unsigned long level = strtoul(buf, &end, 10);
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| 214 | /* paranoid */ verifyf(level <= 250, "Cpu %u has more than 250 levels of cache, this is not supported", cpu);
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| 215 |
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| 216 | // shared_cpu_list is a range of cpus that share this particular cache
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| 217 | size_t n = read_cpuidxinfo_into(cpu, idx, "shared_cpu_list", buf, 32);
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| 218 | /* paranoid */ verify( buf[n-1] == '\n' );
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| 219 | buf[n-1] = '\0';
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| 220 |
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| 221 | // Simply call the functor
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| 222 | handle(idx, level, buf, n - 1);
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| 223 | }
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| 224 | }
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| 225 |
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| 226 |
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| 227 | struct raw_cache_instance {
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| 228 | idx_range_t range;
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| 229 | unsigned width;
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| 230 | unsigned char level;
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| 231 | // FIXME add at least size and type
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| 232 | };
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| 233 |
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| 234 | static void ?{}(raw_cache_instance & this) { this.range = 0p;}
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| 235 | static void ^?{}(raw_cache_instance & this) { free(this.range);}
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| 236 |
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| 237 | raw_cache_instance ** build_raw_cache_table(unsigned cpus, unsigned idxs, unsigned cache_levels)
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| 238 | {
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| 239 | raw_cache_instance ** raw = alloc(cpus);
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| 240 | for(i; cpus) {
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| 241 | raw[i] = alloc(cache_levels);
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| 242 | void addcache(unsigned fidx, unsigned char level, idx_range_t range, size_t len) {
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| 243 | /* paranoid */ verifyf(level <= cache_levels, "Unexpected cache level %d on cpu %u index %u", (int)level, i, fidx);
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| 244 |
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| 245 | unsigned idx = cache_levels - level;
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| 246 | raw_cache_instance & r = raw[i][idx];
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| 247 | r.range = strndup(range, len);
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| 248 | r.level = level;
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| 249 | const char * end;
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| 250 | r.width = read_width(range, len, &end);
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| 251 | }
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| 252 | foreach_cacheidx(i, idxs, addcache);
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| 253 | }
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| 254 |
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| 255 | #if defined(__CFA_WITH_VERIFY__)
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| 256 | // Check widths are consistent
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| 257 | for(i; 1~cpus) {
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| 258 | for(j; cache_levels) {
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| 259 | verifyf(raw[0][j].width == raw[i][j].width, "Unexpected width %u for cpu %u, index %u. Expected %u.", raw[i][j].width, i, j, raw[0][j].width);
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| 260 | }
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| 261 | }
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| 262 | #endif
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| 263 |
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| 264 | return raw;
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| 265 | }
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| 266 |
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| 267 | // returns an allocate list of all the different distinct last level caches
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| 268 | static [*idx_range_t, size_t cnt] distinct_llcs(unsigned cpus, unsigned llc_idx, raw_cache_instance ** raw) {
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| 269 | // Allocate at least one element
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| 270 | idx_range_t * ranges = alloc();
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| 271 | size_t range_cnt = 1;
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| 272 |
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| 273 | // Initialize with element 0
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| 274 | *ranges = raw[0][llc_idx].range;
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| 275 |
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| 276 | // Go over all other cpus
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| 277 | CPU_LOOP: for(i; 1~cpus) {
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| 278 | // Check if the range is already there
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| 279 | idx_range_t candidate = raw[i][llc_idx].range;
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| 280 | for(j; range_cnt) {
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| 281 | idx_range_t exist = ranges[j];
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| 282 | // If the range is already there just jump to the next cpu
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| 283 | if(0 == strcmp(candidate, exist)) continue CPU_LOOP;
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| 284 | }
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| 285 |
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| 286 | // The range wasn't there, added to the list
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| 287 | ranges = alloc(range_cnt + 1, ranges`realloc);
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| 288 | ranges[range_cnt] = candidate;
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| 289 | range_cnt++;
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| 290 | }
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| 291 |
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| 292 | // return what we have
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| 293 | return [ranges, range_cnt];
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| 294 | }
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| 295 |
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| 296 | struct cpu_pairing_t {
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| 297 | unsigned cpu;
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| 298 | unsigned llc_id;
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| 299 | };
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| 300 |
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| 301 | int ?<?( cpu_pairing_t lhs, cpu_pairing_t rhs ) {
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| 302 | return lhs.llc_id < rhs.llc_id;
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| 303 | }
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| 304 |
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| 305 | static [[]cpu_pairing_t] get_cpu_pairings(unsigned cpus, raw_cache_instance ** raw, idx_range_t * maps, size_t map_cnt) {
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| 306 | cpu_pairing_t * pairings = alloc(cpus);
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| 307 |
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| 308 | CPU_LOOP: for(i; cpus) {
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| 309 | pairings[i].cpu = i;
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| 310 | idx_range_t want = raw[i][0].range;
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| 311 | MAP_LOOP: for(j; map_cnt) {
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| 312 | if(0 != strcmp(want, maps[j])) continue MAP_LOOP;
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| 313 |
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| 314 | pairings[i].llc_id = j;
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| 315 | continue CPU_LOOP;
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| 316 | }
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| 317 |
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| 318 | /* paranoid */ verifyf( false, "Cpu %u map doesn't match", i );
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| 319 | }
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| 320 |
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| 321 | return pairings;
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| 322 | }
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| 323 |
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| 324 | extern "C" {
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| 325 | void __cfaabi_device_startup( void ) {
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| 326 | int cpus = count_cpus();
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| 327 | int idxs = count_cache_indexes();
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| 328 |
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| 329 | // Count actual cache levels
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| 330 | unsigned cache_levels = 0;
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| 331 | unsigned llc = 0;
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| 332 | {
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| 333 | unsigned char prev = -1u;
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| 334 | void first(unsigned idx, unsigned char level, const char * map, size_t len) {
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| 335 | /* paranoid */ verifyf(level < prev, "Index %u of cpu 0 has cache levels out of order: %u then %u", idx, (unsigned)prev, (unsigned)level);
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| 336 | llc = max(llc, level);
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| 337 | prev = level;
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| 338 | cache_levels++;
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| 339 | }
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| 340 | foreach_cacheidx(0, idxs, first);
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| 341 | }
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| 342 |
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| 343 | // Read in raw data
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| 344 | raw_cache_instance ** raw = build_raw_cache_table(cpus, idxs, cache_levels);
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| 345 |
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| 346 | // Find number of distinct cache instances
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| 347 | idx_range_t * maps;
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| 348 | size_t map_cnt;
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| 349 | [maps, map_cnt] = distinct_llcs(cpus, cache_levels - llc, raw);
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| 350 |
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| 351 | /* paranoid */ verify((map_cnt * raw[0][cache_levels - llc].width) == cpus);
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| 352 |
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| 353 | // Get mappings from cpu to cache instance
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| 354 | cpu_pairing_t * pairings = get_cpu_pairings(cpus, raw, maps, map_cnt);
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| 355 |
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| 356 | // Sort by cache instance
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| 357 | qsort(pairings, cpus);
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| 358 |
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| 359 | unsigned llc_width = raw[0][cache_levels - llc].width;
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| 360 |
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| 361 | // From the mappins build the actual cpu map we want
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| 362 | struct cpu_map_entry_t * entries = alloc(cpus);
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| 363 | for(i; cpus) { entries[i].count = 0; }
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| 364 | for(i; cpus) {
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| 365 | unsigned c = pairings[i].cpu;
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| 366 | entries[c].start = pairings[i].llc_id * llc_width;
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| 367 | entries[c].count = llc_width;
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| 368 | }
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| 369 |
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| 370 | // get rid of the temporary data
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| 371 | free(maps);
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| 372 | free(pairings);
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| 373 |
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| 374 | for(i; cpus) {
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| 375 | for(j; cache_levels) {
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| 376 | ^(raw[i][j]){};
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| 377 | }
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| 378 | free(raw[i]);
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| 379 | }
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| 380 | free(raw);
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| 381 |
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| 382 | cpu_info.llc_map = entries;
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| 383 | cpu_info.hthrd_count = cpus;
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| 384 | }
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| 385 |
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| 386 | void __cfaabi_device_shutdown( void ) {
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| 387 | free(cpu_info.llc_map);
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| 388 | }
|
|---|
| 389 | }
|
|---|
