{"id":1684,"date":"2020-08-19T21:00:10","date_gmt":"2020-08-19T13:00:10","guid":{"rendered":"https:\/\/blog.dynox.cn\/?p=1684"},"modified":"2023-08-07T02:03:10","modified_gmt":"2023-08-06T18:03:10","slug":"1684","status":"publish","type":"post","link":"https:\/\/blog.dynox.cn\/?p=1684","title":{"rendered":"CPU Cache\u6d4b\u91cf\u65b9\u6cd5"},"content":{"rendered":"<div class=\"gruber-markdown\"><p>\u901a\u8fc7\u4e0a\u4e00\u7bc7\u6587\u7ae0\u300a<a href=\"https:\/\/blog.dynox.cn\/?p=1682\">\u901a\u8fc7TSC\u89c2\u5bdfCPU<\/a>\u300b\u77e5\u9053\u4e86\u53ef\u4ee5\u901a\u8fc7TSC\u6765\u6d4b\u91cfCPU\u7684\u5185\u90e8\u884c\u4e3a\uff0c\u672c\u6587\u5c06\u4ecb\u7ecdCPU Cache\u7684\u7ed3\u6784\u53ca\u51e0\u79cd\u5e38\u7528\u7684\u6d4b\u91cf\u624b\u6cd5\uff1a<\/p>\n<h1>Cache\u7684\u5206\u7ea7\u7ed3\u6784<\/h1>\n<p><img decoding=\"async\" src=\"https:\/\/\/blog.dynox.cn\/wp-content\/uploads\/2020\/08\/CPU-Memory-Cache-Hierarchy.png\" alt=\"Memory & Cache\u7684\u5206\u7ea7\u7ed3\u6784\" \/><\/p>\n<ul>\n<li>Cache \u662f\u5206\u7ea7\u7684\uff1a\u4e00\u822c\u5206\u4e3a3\u7ea7\uff0c\u8f83\u8001\u7684CPU\u5982Core 2 Duo\u53ea\u67092\u7ea7\u3002L1\u662f\u96c6\u6210\u662fcore\u5185\u90e8\u7684\uff0c\u6307\u4ee4\u4e0e\u6570\u636eCache\u662f\u5206\u79bb\u7684\uff0c\u597dL1C\u548cL1D\uff1bL2\u662f\u7d27\u8d34core\u7684\uff1bL3\u662f\u591a\u6838\u5171\u4eab\u7684\uff0c\u6bcf\u4e2acore\u6709\u81ea\u5df1\u7684Slice\uff0c\u901a\u8fc7Ring Bus\u6216Mesh\u7ed3\u6784\u4e92\u8054\u4e92\u8bbf<\/li>\n<li>Cache\u4ee5Cache Line\u4e3a\u8bbf\u95ee\u5355\u4f4d\uff0c\u5373Cache\u53ca\u5185\u5b58\u7684\u8bbf\u95ee\u662f\u4ee5\u5757\u4e3a\u5355\u4f4d\u7684\uff0c\u800c\u4e0d\u662f\u5b57\u8282\u5355\u4f4d\u3002\u8f83\u65b0\u7684X86 CPU\u7684Cache Line\u4e00\u822c\u662f64\u5b57\u8282\u3002\u4e0a\u4e00\u7bc7\u6587\u7ae0\u901a\u8fc7TSC\u89c2\u5bdfCPU\u66fe\u6ce8\u610f\u5230\u4e00\u4e2a\u6709\u8da3\u7684\u6d4b\u91cf\u7ed3\u679c\uff1aX86\u7a0b\u5e8f\u8bbf\u95ee\u4e00\u4e2a1\u5b57\u8282\u4e0e\u8bbf\u95ee2\u4e2a\u30014\u4e2a\u53ca8\u4e2a\u5b57\u8282\u7684\u5ef6\u8fdb\u5747\u4e3a31\u4e2a\u6307\u4ee4\u5468\u671f\uff0c\u5e76\u4e0d\u662f\u7ebf\u6027\u589e\u957f\u7684\uff0c\u5c31\u662f\u8fd9\u4e2a\u539f\u56e0<\/li>\n<li>\u5c42\u7ea7\u5305\u542b\u4e0e\u5426\u7531CPU\u5b9e\u73b0\u51b3\u5b9a\uff1aL2\u4e00\u822c\u90fd\u662f\u5305\u542bL1\u7684\u5168\u90e8\u5185\u5bb9\u7684\uff0cL3\u53ef\u4ee5\u662fNon-inclusive\uff0c\u4e5f\u53ef\u4ee5\u662fExclusive\u3002Intel\u7684CPU\u4e00\u822c\u662f\u5305\u542b\u7684\uff0c\u4f46AMD\u7684Zen\u7cfb\u5217CPU\u7684L3\u5c31\u662f\u5b9a\u4e49\u4e3aL1\/L2\u7684Victim Cache\uff0cVictim\u662f\u6307\u4eceL1\u53caL2\u4e2d\u79fb\u9664\u7684Cache\u9879<\/li>\n<li>Cache\u81ea\u8eab\u7684\u6784\u9020\u91c7\u7528\u201c\u7ec4\u76f8\u8054\u201d\u65b9\u5f0f<\/li>\n<\/ul>\n<h1>Cache\u4e0d\u540c\u5206\u7ea7\u7684\u6027\u80fd<\/h1>\n<p><img decoding=\"async\" src=\"https:\/\/\/blog.dynox.cn\/wp-content\/uploads\/2020\/08\/CPU-Memory-Cache-Performance.png\" alt=\"Memory & Cache\u6027\u80fd\u6570\u636e\" \/><\/p>\n<p>\u5728\u4e0a\u56fe\u4e2d\u770b\u5230Cache\u662f\u5206\u7ea7\u7684\uff0c\u7528\u4e0d\u540c\u7ea7\u7684\u8bbf\u95ee\u901f\u5ea6\u6709\u5f88\u5927\u4e0d\u540c\uff0c\u6545\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u5236\u9020\u51b2\u7a81\u6216\u76f4\u63a5Flush Cache\u7684\u65b9\u5f0f\u5c06\u6570\u636e\u4eceCache\u4e2d\u6e05\u9664\uff0c\u4ece\u800c\u901a\u8fc7\u524d\u540e\u5185\u5b58\u8bbf\u95ee\u7684\u65f6\u95f4\u5dee\u6765\u8fdb\u884c\u5224\u5b9a\u3002<\/p>\n<h1>\u6d4b\u91cf\u65b9\u6cd5<\/h1>\n<p>\u5236\u9020\u51b2\u7a81\u4ee5\u6e05\u9664Cache\u7684\u5e38\u7528\u624b\u6bb5\u6709\u4ee5\u4e0b\u51e0\u79cd\u3010\u53c2\u9605 1\uff1aCache side channel attacks: CPU Design as a security problem by Anders Fog]\u3011\uff1a<\/p>\n<ol>\n<li>Evict (\u9a71\u9010) + Time (\u6d4b\u91cf) \uff1a \u901a\u8fc7\u5236\u9020\u51b2\u7a81\u4ee5\u8fbe\u6210\u88ab\u6d4b\u91cf\u76ee\u6807\u6570\u636e\u4ececache\u4e2d\u6e05\u9664\u7684\u76ee\u7684<\/li>\n<li>Prime (\u88c5\u586b) + Probe (\u63a2\u6d4b) \uff1a\u4e0e1)\u65b9\u6cd5\u4e00\u6837\uff0c\u53ea\u662f\u4f5c\u7528\u5bf9\u8c61\u662f\u53cd\u7684<\/li>\n<li>Flush (\u51b2\u5237) + Reload (\u52a0\u8f7d) ) \uff1a\u6700\u4e3b\u52a8\u548c\u6700\u5feb\u7684\u529e\u6cd5\uff0c\u76f4\u63a5\u5229\u7528clflush\u6307\u4ee4\u5237\u65b0\uff0c\u7136\u540e\u518d\u8bfb\u53d6\u5185\u5b58\uff0c\u6b64\u65f6\u4f1a\u53d1\u751fCache Miss\u4e8b\u4ef6\u3002<\/li>\n<li>Flush (\u51b2\u5237) + Flush (\u51b2\u5237) ) \uff1a\u4e0e3)\u7c7b\u4f3c\uff0c\u4f46\u6d4b\u91cf\u7684\u662fclflush\u6307\u4ee4\u9488\u5bf9\u6570\u636e\u5728\u4e0d\u5728cache\u4e2d\u7684\u6267\u884c\u5468\u671f\u7684\u4e0d\u540c\n\u5728\u6761\u4ef6\u8bb8\u53ef\u7684\u60c5\u51b5\u4e0b\uff0c\u5c3d\u91cf\u91c7\u7528\u7b2c3\u79cd\uff0c\u5373\u6700\u5feb\u7684\u529e\u6cd5\u3002<\/li>\n<\/ol>\n<h1>\u5b9e\u4f8b\uff1aFlush + Reload<\/h1>\n<p>Flush\u5373clflush\u6307\u4ee4\uff0cVisual C++\u4e2d\u5b9a\u4e49\u5982\u4e0b\uff1a<\/p>\n<pre><code class=\"prettyprint\" class=\"language-c\">        extern void _mm_clflush(void const*_P);<\/code><\/pre>\n<p>\u6d4b\u91cf\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"prettyprint\" class=\"language-c\">        \/* flush *\/\n        _mm_clflush(&amp;amp;data[0]);\n\n        \/* measure cache miss latency *\/\n        ts = rdtscp(&amp;amp;ui);\n        m |= data[0];\n        te = rdtscp(&amp;amp;ui);<\/code><\/pre>\n<h1>\u5b9e\u6218\uff1aCache Line\u7684\u6d4b\u91cf<\/h1>\n<p><strong>\u539f\u7406\uff1a<\/strong>\n<img decoding=\"async\" src=\"https:\/\/\/blog.dynox.cn\/wp-content\/uploads\/2020\/08\/CPU-Memory-Cache-MeasureMethod.jpg\" alt=\"Cache\u6027\u80fd\u6d4b\u91cf\u65b9\u6cd5\" \/><\/p>\n<p><strong>\u7ed3\u8bba\uff1a<\/strong>\n<img decoding=\"async\" src=\"https:\/\/\/blog.dynox.cn\/wp-content\/uploads\/2020\/08\/CPU-Memory-Cache-MeasureResults1.jpg\" alt=\"Cache\u6027\u80fd\u7ed3\u679c\" \/><\/p>\n<p>\u4ece\u56fe\u4e2d\u6211\u4eec\u53ef\u4ee5\u770b\u523064\u5b57\u8282\u662f\u4e00\u4e2a\u660e\u663e\u7684\u5206\u754c\u70b9\u3002<\/p>\n<p><strong>\u786c\u4ef6\u9884\u53d6: Hardware Prefetcher<\/strong><\/p>\n<p>\u5982\u679c\u4f60\u5728\u81ea\u5df1\u7684\u7535\u8111\u4e0a\u8fdb\u884c\u6d4b\u8bd5\uff0c\u4f60\u770b\u5230\u7684\u53ef\u80fd\u4e0d\u662f\u4e0a\u56fe\u6240\u793a\u7684\u6837\u5b50\uff0c\u5f88\u5927\u7684\u53ef\u80fd\u5982\u4e0b\u56fe\u6240\u793a\uff0c\u660e\u663e\u7684\u5206\u754c\u70b9\u4e0d\u662f64\u5b57\u8282\u800c\u662f128\u5b57\u8282\uff1a\n<img decoding=\"async\" src=\"https:\/\/\/blog.dynox.cn\/wp-content\/uploads\/2020\/08\/CPU-Memory-Cache-MeasureResults2.jpg\" alt=\"Cache\u6027\u80fd\u7ed3\u679c\" \/><\/p>\n<p>\u8fd9\u662f\u56e0\u4e3a\u786c\u4ef6\u9884\u53d6\u5373HWPrefetcher\u7684\u7f18\u6545\uff0c\u5e76\u4e14\u786c\u4ef6\u9884\u53d6\u9ed8\u90fd\u662f\u5f00\u542f\u7684\u3002\u786c\u4ef6\u9884\u53d6\u529f\u80fd\u4f1a\u5728\u6bcf\u6b21Cache Miss\u7684\u60c5\u51b5\u4e0b\u591a\u8bfb\u4e00\u4e2aCache Line\uff0c\u53ef\u4ee5\u7406\u89e3\u4e3a\u6bcf\u6b21\u8bfb\u53d6\u4e24\u4e2aCache Line\u537364 * 2 = 128\u5b57\u8282\uff0c\u4f46\u6570\u636e\u5e76\u4e0d\u662f\u540c\u65f6\u5230\u8fbe\u7684\uff0c\u7b2c\u4e8c\u4e2aCache Line\u7684\u6570\u636e\u7684\u5230\u8fbe\u5468\u671f\u4f1a\u665a\u4e9b\uff0c\u8fd9\u4e5f\u662f\u4e3a\u4ec0\u4e48\u5728128\u8fd9\u4e2a\u70b9\u4e0a\u7684\u5ef6\u65f6\u4f1a\u6bd464\u9ad8\u3002\n<img decoding=\"async\" src=\"https:\/\/\/blog.dynox.cn\/wp-content\/uploads\/2020\/08\/CPU-Memory-Cache-HWPrefetch.png\" alt=\"CPU Cache Prefetcher\" \/><\/p>\n<p><strong>\u5982\u4f55\u5173\u95ed\u786c\u4ef6\u9884\u53d6:<\/strong><\/p>\n<ol>\n<li>\u901a\u8fc7BIOS\u8bbe\u7f6e\uff1a \u901a\u8fc7BIOS\u9009\u9879\u6765\u5173\u95edhwprefetcher\uff0c\u5bf9\u6240\u6709\u7684CPU\u751f\u6548<\/li>\n<li>\u901a\u8fc7\u5185\u6838\u8c03\u8bd5\u5668windbg\u76f4\u63a5\u5173\u95ed\uff1a\u901a\u8fc7\u76f4\u63a5\u6539\u5199msr\u5bc4\u5b58\u5668\u5173\u95ed\u5f53\u524d\u6838\u7684\u786c\u4ef6\u9884\u53d6\u529f\u80fd:\n<pre><code class=\"prettyprint\" class=\"language-c\">0: kd&amp;gt; rdmsr 0x1a4\nmsr[1a4] = 00000000&amp;#x60;00000000\n0: kd&amp;gt; wrmsr 0x1a4 0x0f\n0: kd&amp;gt; ~1\n1: kd&amp;gt; rdmsr 0x1a4\nmsr[1a4] = 00000000&amp;#x60;00000000\n1: kd&amp;gt; wrmsr 0x1a4 0x0f\n1: kd&amp;gt; rdmsr 0x1a4\nmsr[1a4] = 00000000&amp;#x60;0000000f\n1: kd&amp;gt; ~0<\/code><\/pre><\/li>\n<\/ol>\n<h1>\u5b9e\u6218\uff1aCache\u4e0d\u540c\u5206\u7ea7\u7684\u8bbf\u95ee\u5ef6\u65f6\u6d4b\u91cf<\/h1>\n<p>\u5982\u679c\u6211\u4eec\u4ee5\u66f4\u5927\u7684\u7684stride\u8fdb\u884c\u540c\u6837\u7684\u6d4b\u8bd5\u5219\u53ef\u4ee5\u6d4b\u91cf\u51faCache\u6bcf\u4e00\u7ea7\u7684\u5927\u5c0f\uff0c\u5373L1D\uff0cL2\uff0cLLC\u548c\u5185\u5b58\u8bbf\u95ee\u7684\u5ef6\u65f6\u3002\u4e0b\u56fe\u4e2d\u6211\u4eec\u5206\u522b\u4ee51K\u30012K\uff0c\u76f4\u81f364M\u7684stride\u6d4b\u91cf\u51fa\u6765\u7ed3\u679c\uff1a\n<img decoding=\"async\" src=\"https:\/\/\/blog.dynox.cn\/wp-content\/uploads\/2020\/08\/CPU-Memory-Cache-Hierarchy-Final.png\" alt=\"Cache\u6027\u80fd\u7ed3\u679c\" \/>\n\u53ef\u4ee5\u770b\u5230\u6574\u4e2a\u66f2\u7ebf\u67094\u4e2a\u5e73\u53f0\uff0c\u5206\u522b\u8868\u793aL1D\u3001L2\u3001LLC\u548c\u5185\u5b58\u3002L1D\u7684\u5927\u5c0f\u4e3a32K\uff0cL2\u4e3a256K\uff0c\u8fd9\u90e8\u5206\u548cCPUZ\u7684\u8f93\u51fa\u662f\u4e00\u81f4\u7684\u3002\n\u4f46\u7b2c\u4e09\u4e2a\u5e73\u53f0\u5305\u542b\u4e86512K\u30011M\u53ca2M\uff0c\u4ece4M\u5f00\u59cb\u5ef6\u8fdb\u6709\u660e\u663e\u7684\u8dc3\u5347\uff0c\u4ece8M\u4e4b\u540e\u57fa\u672c\u7a33\u5b9a\u5728\u9ad8\u4f4d\u3002\u8fd9\u91cc\u5c31\u6d89\u53ca\u5230\u4e86LLC\u7ec4\u7ec7\u7684\u4e0d\u540c\uff1aL1D\u53caL2 Cache\u90fd\u662f\u4e0e\u7269\u7406\u6838\uff08Core\uff09\u7ed1\u5b9a\u7684\uff0c\u800cLLC\u662f\u7ed1\u5b9aCPU\u7684\uff0c\u53732\u6838\u7684CPU\u7684\u4e24\u4e2a\u6838\u5fc3\u4f1a\u5171\u4eab\u540c\u4e00\u4e2aLLC\uff0c\u6574\u4e2aLLC\u662f\u5e73\u5747\u5206\u914d\u7ed9\u6bcf\u4e2a\u6838\u7684\uff0c\u7136\u540e\u6bcf\u4e2a\u6838\u5fc3\u7684LLC\u901a\u8fc7Ring Bus\u4e92\u8054\uff0c\u5373\u6bcf\u4e2a\u6838\u53c8\u53ef\u4ee5\u8bbf\u95ee\u6240\u6709\u7684LLC\u3002\u8fd9\u91cc\u57284M\u7684stride\u53d1\u751f\u6ce2\u52a8\u7684\u539f\u56e0\u6709\u4e24\u4e2a\uff1a<\/p>\n<ol>\n<li>\u5f53\u524d\u8fd0\u884c\u6d4b\u91cf\u7a0b\u5e8f\u7684CPU\u6838\u5fc3\u7528\u5c3d\u81ea\u5df1\u7684LLC\u540e\u4f1a\u901a\u8fc7Ring Bus\u7ade\u4e89\u8bbf\u95ee\u53e6\u4e00\u4e2a\u6838\u5fc3\u7684LLC<\/li>\n<li>\u6d4b\u91cf\u7a0b\u5e8f\u8fd0\u884c\u65f6\u6574\u4e2a\u64cd\u4f5c\u7cfb\u7edf\u4e5f\u5728\u8fd0\u884c\uff0c\u6240\u4ee5\u6574\u4e2a\u7cfb\u7edf\u5747\u4f1a\u7ade\u4e89\u4f7f\u7528LLC\uff0c\u5fc5\u7136\u4f1a\u5e26\u6765\u6324\u51fa\u6548\u5e94\uff0c\u4ece\u800c\u589e\u5927\u4e86\u5ef6\u65f6<\/li>\n<\/ol>\n<h1>\u53c2\u8003\u8d44\u6599<\/h1>\n<ol>\n<li><a href=\"https:\/\/archive.conference.hitb.org\/hitbsecconf2016ams\/sessions\/cache-side-channel-attacks-cpu-design-as-a-security-problem\/#\">CSCA: Cache side channel attacks: CPU Design as a security problem by Anders Fogh<\/a><\/li>\n<li><a href=\"https:\/\/www.intel.com\/content\/www\/us\/en\/developer\/topic-technology\/high-performance-computing\/overview.html\">HWPF: Disclosure of Hardware Prefetcher Control on Some Intel\u00ae Processors<\/a><\/li>\n<li><a href=\"https:\/\/github.com\/matt-wu\/CPU\/tree\/develop\/CacheLatency\">SourceCode: CacheLatency Github Repo<\/a><\/li>\n<\/ol><\/div>","protected":false},"excerpt":{"rendered":"<p>\u901a\u8fc7\u4e0a\u4e00\u7bc7\u6587\u7ae0\u300a\u901a\u8fc7TSC\u89c2\u5bdfCPU\u300b\u77e5\u9053\u4e86\u53ef\u4ee5\u901a\u8fc7TSC\u6765\u6d4b\u91cfCPU\u7684\u5185\u90e8\u884c\u4e3a\uff0c\u672c\u6587\u5c06\u4ecb\u7ecdCPU Cache [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"footnotes":""},"categories":[9],"tags":[626,622,629,627,628],"views":1322,"_links":{"self":[{"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=\/wp\/v2\/posts\/1684"}],"collection":[{"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1684"}],"version-history":[{"count":2,"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=\/wp\/v2\/posts\/1684\/revisions"}],"predecessor-version":[{"id":1689,"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=\/wp\/v2\/posts\/1684\/revisions\/1689"}],"wp:attachment":[{"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1684"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1684"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.dynox.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1684"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}