1/* x86 cache info.
2 Copyright (C) 2020-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <assert.h>
20#include <unistd.h>
21#include <cpuid.h>
22#include <cpu-features.h>
23
24#if HAVE_TUNABLES
25# define TUNABLE_NAMESPACE cpu
26# include <unistd.h> /* Get STDOUT_FILENO for _dl_printf. */
27# include <elf/dl-tunables.h>
28#endif
29
30#if IS_IN (libc)
31/* Data cache size for use in memory and string routines, typically
32 L1 size, rounded to multiple of 256 bytes. */
33long int __x86_data_cache_size_half attribute_hidden = 32 * 1024 / 2;
34long int __x86_data_cache_size attribute_hidden = 32 * 1024;
35/* Similar to __x86_data_cache_size_half, but not rounded. */
36long int __x86_raw_data_cache_size_half attribute_hidden = 32 * 1024 / 2;
37/* Similar to __x86_data_cache_size, but not rounded. */
38long int __x86_raw_data_cache_size attribute_hidden = 32 * 1024;
39/* Shared cache size for use in memory and string routines, typically
40 L2 or L3 size, rounded to multiple of 256 bytes. */
41long int __x86_shared_cache_size_half attribute_hidden = 1024 * 1024 / 2;
42long int __x86_shared_cache_size attribute_hidden = 1024 * 1024;
43/* Similar to __x86_shared_cache_size_half, but not rounded. */
44long int __x86_raw_shared_cache_size_half attribute_hidden = 1024 * 1024 / 2;
45/* Similar to __x86_shared_cache_size, but not rounded. */
46long int __x86_raw_shared_cache_size attribute_hidden = 1024 * 1024;
47
48/* Threshold to use non temporal store. */
49long int __x86_shared_non_temporal_threshold attribute_hidden;
50
51/* Threshold to use Enhanced REP MOVSB. */
52long int __x86_rep_movsb_threshold attribute_hidden = 2048;
53
54/* Threshold to use Enhanced REP STOSB. */
55long int __x86_rep_stosb_threshold attribute_hidden = 2048;
56
57static void
58init_cacheinfo (void)
59{
60 const struct cpu_features *cpu_features = __get_cpu_features ();
61 long int data = cpu_features->data_cache_size;
62 __x86_raw_data_cache_size_half = data / 2;
63 __x86_raw_data_cache_size = data;
64 /* Round data cache size to multiple of 256 bytes. */
65 data = data & ~255L;
66 __x86_data_cache_size_half = data / 2;
67 __x86_data_cache_size = data;
68
69 long int shared = cpu_features->shared_cache_size;
70 __x86_raw_shared_cache_size_half = shared / 2;
71 __x86_raw_shared_cache_size = shared;
72 /* Round shared cache size to multiple of 256 bytes. */
73 shared = shared & ~255L;
74 __x86_shared_cache_size_half = shared / 2;
75 __x86_shared_cache_size = shared;
76
77 __x86_shared_non_temporal_threshold
78 = cpu_features->non_temporal_threshold;
79
80 __x86_rep_movsb_threshold = cpu_features->rep_movsb_threshold;
81 __x86_rep_stosb_threshold = cpu_features->rep_stosb_threshold;
82}
83#endif
84