1 // SPDX-License-Identifier: GPL-2.0-only !! 1 #include <stdio.h>
2 #include <string.h> !! 2 #include <stdlib.h>
>> 3 #include <unistd.h>
>> 4 #include <linux/bitops.h>
3 #include "api/fs/fs.h" 5 #include "api/fs/fs.h"
4 #include "cputopo.h" <<
5 #include "smt.h" 6 #include "smt.h"
6 7
7 bool smt_on(void) !! 8 /**
>> 9 * hweight_str - Returns the number of bits set in str. Stops at first non-hex
>> 10 * or ',' character.
>> 11 */
>> 12 static int hweight_str(char *str)
>> 13 {
>> 14 int result = 0;
>> 15
>> 16 while (*str) {
>> 17 switch (*str++) {
>> 18 case '':
>> 19 case ',':
>> 20 break;
>> 21 case '1':
>> 22 case '2':
>> 23 case '4':
>> 24 case '8':
>> 25 result++;
>> 26 break;
>> 27 case '3':
>> 28 case '5':
>> 29 case '6':
>> 30 case '9':
>> 31 case 'a':
>> 32 case 'A':
>> 33 case 'c':
>> 34 case 'C':
>> 35 result += 2;
>> 36 break;
>> 37 case '7':
>> 38 case 'b':
>> 39 case 'B':
>> 40 case 'd':
>> 41 case 'D':
>> 42 case 'e':
>> 43 case 'E':
>> 44 result += 3;
>> 45 break;
>> 46 case 'f':
>> 47 case 'F':
>> 48 result += 4;
>> 49 break;
>> 50 default:
>> 51 goto done;
>> 52 }
>> 53 }
>> 54 done:
>> 55 return result;
>> 56 }
>> 57
>> 58 int smt_on(void)
8 { 59 {
9 static bool cached; 60 static bool cached;
10 static bool cached_result; !! 61 static int cached_result;
11 int fs_value; !! 62 int cpu;
>> 63 int ncpu;
12 64
13 if (cached) 65 if (cached)
14 return cached_result; 66 return cached_result;
15 67
16 if (sysfs__read_int("devices/system/cp !! 68 if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) >= 0) {
17 cached_result = (fs_value == 1 !! 69 cached = true;
18 else !! 70 return cached_result;
19 cached_result = cpu_topology__ !! 71 }
20 72
>> 73 cached_result = 0;
>> 74 ncpu = sysconf(_SC_NPROCESSORS_CONF);
>> 75 for (cpu = 0; cpu < ncpu; cpu++) {
>> 76 unsigned long long siblings;
>> 77 char *str;
>> 78 size_t strlen;
>> 79 char fn[256];
>> 80
>> 81 snprintf(fn, sizeof fn,
>> 82 "devices/system/cpu/cpu%d/topology/thread_siblings", cpu);
>> 83 if (sysfs__read_str(fn, &str, &strlen) < 0) {
>> 84 snprintf(fn, sizeof fn,
>> 85 "devices/system/cpu/cpu%d/topology/core_cpus", cpu);
>> 86 if (sysfs__read_str(fn, &str, &strlen) < 0)
>> 87 continue;
>> 88 }
>> 89 /* Entry is hex, but does not have 0x, so need custom parser */
>> 90 siblings = hweight_str(str);
>> 91 free(str);
>> 92 if (siblings > 1) {
>> 93 cached_result = 1;
>> 94 break;
>> 95 }
>> 96 }
21 cached = true; 97 cached = true;
22 return cached_result; 98 return cached_result;
23 } <<
24 <<
25 bool core_wide(bool system_wide, const char *u <<
26 { <<
27 /* If not everything running on a core <<
28 if (!system_wide) <<
29 return false; <<
30 <<
31 /* Cheap case that SMT is disabled and <<
32 if (!smt_on()) <<
33 return true; <<
34 <<
35 return cpu_topology__core_wide(online_ <<
36 } 99 }
37 100
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