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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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51204e0639
cpufreq_quick_get() allows cpufreq drivers to over-ride cpu_khz that is otherwise reported in x86 /proc/cpuinfo "cpu MHz". There are four problems with this scheme, any of them is sufficient justification to delete it. 1. Depending on which cpufreq driver is loaded, the behavior of this field is different. 2. Distros complain that they have to explain to users why and how this field changes. Distros have requested a constant. 3. The two major providers of this information, acpi_cpufreq and intel_pstate, both "get it wrong" in different ways. acpi_cpufreq lies to the user by telling them that they are running at whatever frequency was last requested by software. intel_pstate lies to the user by telling them that they are running at the average frequency computed over an undefined measurement. But an average computed over an undefined interval, is itself, undefined... 4. On modern processors, user space utilities, such as turbostat(1), are more accurate and more precise, while supporing concurrent measurement over arbitrary intervals. Users who have been consulting /proc/cpuinfo to track changing CPU frequency will be dissapointed that it no longer wiggles -- perhaps being unaware of the limitations of the information they have been consuming. Yes, they can change their scripts to look in sysfs cpufreq/scaling_cur_frequency. Here they will find the same data of dubious quality here removed from /proc/cpuinfo. The value in sysfs will be addressed in a subsequent patch to address issues 1-3, above. Issue 4 will remain -- users that really care about accurate frequency information should not be using either proc or sysfs kernel interfaces. They should be using using turbostat(8), or a similar purpose-built analysis tool. Signed-off-by: Len Brown <len.brown@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
157 lines
3.9 KiB
C
157 lines
3.9 KiB
C
#include <linux/smp.h>
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#include <linux/timex.h>
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#include <linux/string.h>
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#include <linux/seq_file.h>
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/*
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* Get CPU information for use by the procfs.
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*/
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static void show_cpuinfo_core(struct seq_file *m, struct cpuinfo_x86 *c,
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unsigned int cpu)
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{
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#ifdef CONFIG_SMP
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seq_printf(m, "physical id\t: %d\n", c->phys_proc_id);
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seq_printf(m, "siblings\t: %d\n",
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cpumask_weight(topology_core_cpumask(cpu)));
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seq_printf(m, "core id\t\t: %d\n", c->cpu_core_id);
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seq_printf(m, "cpu cores\t: %d\n", c->booted_cores);
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seq_printf(m, "apicid\t\t: %d\n", c->apicid);
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seq_printf(m, "initial apicid\t: %d\n", c->initial_apicid);
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#endif
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}
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#ifdef CONFIG_X86_32
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static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c)
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{
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seq_printf(m,
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"fdiv_bug\t: %s\n"
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"f00f_bug\t: %s\n"
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"coma_bug\t: %s\n"
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"fpu\t\t: %s\n"
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"fpu_exception\t: %s\n"
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"cpuid level\t: %d\n"
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"wp\t\t: yes\n",
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static_cpu_has_bug(X86_BUG_FDIV) ? "yes" : "no",
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static_cpu_has_bug(X86_BUG_F00F) ? "yes" : "no",
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static_cpu_has_bug(X86_BUG_COMA) ? "yes" : "no",
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static_cpu_has(X86_FEATURE_FPU) ? "yes" : "no",
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static_cpu_has(X86_FEATURE_FPU) ? "yes" : "no",
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c->cpuid_level);
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}
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#else
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static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c)
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{
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seq_printf(m,
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"fpu\t\t: yes\n"
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"fpu_exception\t: yes\n"
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"cpuid level\t: %d\n"
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"wp\t\t: yes\n",
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c->cpuid_level);
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}
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#endif
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static int show_cpuinfo(struct seq_file *m, void *v)
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{
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struct cpuinfo_x86 *c = v;
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unsigned int cpu;
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int i;
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cpu = c->cpu_index;
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seq_printf(m, "processor\t: %u\n"
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"vendor_id\t: %s\n"
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"cpu family\t: %d\n"
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"model\t\t: %u\n"
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"model name\t: %s\n",
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cpu,
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c->x86_vendor_id[0] ? c->x86_vendor_id : "unknown",
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c->x86,
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c->x86_model,
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c->x86_model_id[0] ? c->x86_model_id : "unknown");
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if (c->x86_mask || c->cpuid_level >= 0)
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seq_printf(m, "stepping\t: %d\n", c->x86_mask);
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else
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seq_puts(m, "stepping\t: unknown\n");
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if (c->microcode)
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seq_printf(m, "microcode\t: 0x%x\n", c->microcode);
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if (cpu_has(c, X86_FEATURE_TSC))
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seq_printf(m, "cpu MHz\t\t: %u.%03u\n",
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cpu_khz / 1000, (cpu_khz % 1000));
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/* Cache size */
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if (c->x86_cache_size >= 0)
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seq_printf(m, "cache size\t: %d KB\n", c->x86_cache_size);
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show_cpuinfo_core(m, c, cpu);
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show_cpuinfo_misc(m, c);
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seq_puts(m, "flags\t\t:");
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for (i = 0; i < 32*NCAPINTS; i++)
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if (cpu_has(c, i) && x86_cap_flags[i] != NULL)
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seq_printf(m, " %s", x86_cap_flags[i]);
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seq_puts(m, "\nbugs\t\t:");
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for (i = 0; i < 32*NBUGINTS; i++) {
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unsigned int bug_bit = 32*NCAPINTS + i;
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if (cpu_has_bug(c, bug_bit) && x86_bug_flags[i])
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seq_printf(m, " %s", x86_bug_flags[i]);
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}
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seq_printf(m, "\nbogomips\t: %lu.%02lu\n",
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c->loops_per_jiffy/(500000/HZ),
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(c->loops_per_jiffy/(5000/HZ)) % 100);
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#ifdef CONFIG_X86_64
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if (c->x86_tlbsize > 0)
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seq_printf(m, "TLB size\t: %d 4K pages\n", c->x86_tlbsize);
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#endif
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seq_printf(m, "clflush size\t: %u\n", c->x86_clflush_size);
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seq_printf(m, "cache_alignment\t: %d\n", c->x86_cache_alignment);
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seq_printf(m, "address sizes\t: %u bits physical, %u bits virtual\n",
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c->x86_phys_bits, c->x86_virt_bits);
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seq_puts(m, "power management:");
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for (i = 0; i < 32; i++) {
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if (c->x86_power & (1 << i)) {
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if (i < ARRAY_SIZE(x86_power_flags) &&
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x86_power_flags[i])
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seq_printf(m, "%s%s",
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x86_power_flags[i][0] ? " " : "",
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x86_power_flags[i]);
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else
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seq_printf(m, " [%d]", i);
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}
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}
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seq_puts(m, "\n\n");
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return 0;
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}
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static void *c_start(struct seq_file *m, loff_t *pos)
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{
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*pos = cpumask_next(*pos - 1, cpu_online_mask);
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if ((*pos) < nr_cpu_ids)
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return &cpu_data(*pos);
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return NULL;
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}
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static void *c_next(struct seq_file *m, void *v, loff_t *pos)
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{
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(*pos)++;
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return c_start(m, pos);
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}
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static void c_stop(struct seq_file *m, void *v)
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{
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}
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const struct seq_operations cpuinfo_op = {
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.start = c_start,
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.next = c_next,
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.stop = c_stop,
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.show = show_cpuinfo,
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};
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