在Android上以编程方式获取缓存线大小

我进行了一次小调查,发现了一些东西:

首先,看起来 sysconf() 具有 _SC_LEVEL1_ICACHE_SIZE ,则, _SC_LEVEL1_ICACHE_ASSOC ,则, _SC_LEVEL1_ICACHE_LINESIZE 或其他与CPU缓存相关的标志始终返回-1(有时可能是0)和 it seems to be the reason for this ,它们根本没有实现。

但有一个解决方案。使用 this library 如果您能够在项目中使用JNI。此库对于检索有关CPU的信息非常有用(我的设备非常古老):

下面是我用来获取CPU缓存信息的代码:

#include <string>
#include <sstream>
#include <cpuinfo.h>

void get_cache_info(const char* name, const struct cpuinfo_cache* cache, std::ostringstream& oss)
{
    oss << "CPU Cache: " << name << std::endl;
    oss << " > size            : " << cache->size << std::endl;
    oss << " > associativity   : " << cache->associativity << std::endl;
    oss << " > sets            : " << cache->sets << std::endl;
    oss << " > partitions      : " << cache->partitions << std::endl;
    oss << " > line_size       : " << cache->line_size << std::endl;
    oss << " > flags           : " << cache->flags << std::endl;
    oss << " > processor_start : " << cache->processor_start << std::endl;
    oss << " > processor_count : " << cache->processor_count << std::endl;
    oss << std::endl;
}

const std::string get_cpu_info()
{
    cpuinfo_initialize();
    const struct cpuinfo_processor* proc = cpuinfo_get_current_processor();

    std::ostringstream oss;

    if (proc->cache.l1d)
        get_cache_info("L1 Data", proc->cache.l1d, oss);

    if (proc->cache.l1i)
        get_cache_info("L1 Instruction", proc->cache.l1i, oss);

    if (proc->cache.l2)
        get_cache_info("L2", proc->cache.l2, oss);

    if (proc->cache.l3)
        get_cache_info("L3", proc->cache.l3, oss);

    if (proc->cache.l4)
        get_cache_info("L4", proc->cache.l4, oss);

    return oss.str();
}