やってみた(追記＆書き直し)

1.TLBのキャッシュにヒットするreadのコスト
2.invlpgでキャッシュをクリアするコスト
3.invlpgでTLBのキャッシュを無効にしてからread
4.以前と同じループ
計測結果および詳細はこちら(http://mona.sourceforge.jp/dynamic/pukiwiki/pukiwiki/pukiwiki.php?%B5%C4%CF%C0%2F%A5%E1%A5%C3%A5%BB%A1%BC%A5%B8%2FCR3%C0%DA%C2%D8%A5%B3%A5%B9%A5%C8)

disableInterrupt();

dword total;
int count;

total = 0;
count = 0;

for (int i = 0; i < 500; i++)
{
    /* at first flush all */
    g_page_manager->setPageDirectory(cr31);
    g_page_manager->setPageDirectory(cr32);

    dword l1, l2, h1, h2;

    dword* p = (dword*)0x600000;

    /* read and create cache */
    volatile dword test1 = *p;

    rdtsc(&l1, &h1);

    /* read once using cache */
    volatile dword test2 = *p;

    rdtsc(&l2, &h2);

    if (h1 != h2) continue;

    count++;
    total += (l2 - l1);
}

g_console->printf("read using cache: %d\n", total / count);

total = 0;
count = 0;

for (int i = 0; i < 500; i++)
{
    /* at first flush all */
    g_page_manager->setPageDirectory(cr31);
    g_page_manager->setPageDirectory(cr32);

    dword l1, l2, h1, h2;

    dword* p = (dword*)0x600000;

    /* read and create cache */
    volatile dword test1 = *p;

    rdtsc(&l1, &h1);

    asm volatile ("invlpg %0\n": "=m"(p));

    rdtsc(&l2, &h2);

    if (h1 != h2) continue;

    count++;
    total += (l2 - l1);
}

g_console->printf("invlpg: %d\n", total / count);

total = 0;
count = 0;

for (int i = 0; i < 500; i++)
{
    /* at first flush all */
    g_page_manager->setPageDirectory(cr31);
    g_page_manager->setPageDirectory(cr32);

    dword l1, l2, h1, h2;

    dword* p = (dword*)0x600000;

    /* read and create cache */
    volatile dword test1 = *p;

    asm volatile ("invlpg %0\n": "=m"(p));

    rdtsc(&l1, &h1);

    /* read once */
    volatile dword test2 = *p;

    rdtsc(&l2, &h2);

    if (h1 != h2) continue;

    count++;
    total += (l2 - l1);
}

g_console->printf("create cache and read: %d\n", total / count);

total = 0;
count = 0;

for (int i = 0; i < 500; i++)
{
    /* at first flush all */
    g_page_manager->setPageDirectory(cr31);
    g_page_manager->setPageDirectory(cr32);

    dword l1, l2, h1, h2;

    dword* p = (dword*)0x600000;

    /* read and create cache */
    volatile dword test1 = *p;

    rdtsc(&l1, &h1);

    for (int j = 0; j < 10000; j++)
    {
        j++;
        j--;
    }

    rdtsc(&l2, &h2);

    if (h1 != h2) continue;

    count++;
    total += (l2 - l1);
}

g_console->printf("loop: %d\n", total / count);