“`” \u53c2\u8003\u56de\u7b54\uff1a<\/p>\n
1\uff09\u4f4e\u7cbe\u5ea6\u65f6\u949f<\/p>\n
Linux 2.6.16\u4e4b\u524d\uff0c\u5185\u6838\u53ea\u652f\u6301\u4f4e\u7cbe\u5ea6\u65f6\u949f\uff0c\u5185\u6838\u5b9a\u65f6\u5668\u7684\u5de5\u4f5c\u65b9\u5f0f\uff1a<\/p>\n
1\u3001\u7cfb\u7edf\u542f\u52a8\u540e\uff0c\u4f1a\u8bfb\u53d6\u65f6\u949f\u6e90\u8bbe\u5907(RTC, HPET\uff0cPIT\u2026)\uff0c\u521d\u59cb\u5316\u5f53\u524d\u7cfb\u7edf\u65f6\u95f4\u3002<\/p>\n
2\u3001\u5185\u6838\u4f1a\u6839\u636eHZ(\u7cfb\u7edf\u5b9a\u65f6\u5668\u9891\u7387\uff0c\u8282\u62cd\u7387)\u53c2\u6570\u503c\uff0c\u8bbe\u7f6e\u65f6\u949f\u4e8b\u4ef6\u8bbe\u5907\uff0c\u542f\u52a8tick(\u8282\u62cd)\u4e2d\u65ad\u3002HZ\u8868\u793a1\u79d2\u79cd\u4ea7\u751f\u591a\u5c11\u4e2a\u65f6\u949f\u786c\u4ef6\u4e2d\u65ad\uff0ctick\u5c31\u8868\u793a\u8fde\u7eed\u4e24\u4e2a\u4e2d\u65ad\u7684\u95f4\u9694\u65f6\u95f4\u3002<\/p>\n
3\u3001\u8bbe\u7f6e\u65f6\u949f\u4e8b\u4ef6\u8bbe\u5907\u540e\uff0c\u65f6\u949f\u4e8b\u4ef6\u8bbe\u5907\u4f1a\u5b9a\u65f6\u4ea7\u751f\u4e00\u4e2atick\u4e2d\u65ad\uff0c\u89e6\u53d1\u65f6\u949f\u4e2d\u65ad\u5904\u7406\u51fd\u6570\uff0c\u66f4\u65b0\u7cfb\u7edf\u65f6\u949f,\u5e76\u68c0\u6d4btimer wheel\uff0c\u8fdb\u884c\u8d85\u65f6\u4e8b\u4ef6\u7684\u5904\u7406\u3002<\/p>\n
\u5728\u4e0a\u9762\u5de5\u4f5c\u65b9\u5f0f\u4e0b\uff0cLinux 2.6.16 \u4e4b\u524d\uff0c\u5185\u6838\u8f6f\u4ef6\u5b9a\u65f6\u5668\u91c7\u7528timer wheel\u591a\u7ea7\u65f6\u95f4\u8f6e\u7684\u5b9e\u73b0\u673a\u5236\uff0c\u7ef4\u62a4\u64cd\u4f5c\u7cfb\u7edf\u7684\u6240\u6709\u5b9a\u65f6\u4e8b\u4ef6\u3002timer wheel\u7684\u89e6\u53d1\u662f\u57fa\u4e8e\u7cfb\u7edftick\u5468\u671f\u6027\u4e2d\u65ad\u3002<\/p>\n
\u6240\u4ee5\u8bf4\u8fd9\u4e4b\u524d\uff0clinux\u53ea\u80fd\u652f\u6301ms\u7ea7\u522b\u7684\u65f6\u949f\uff0c\u968f\u7740\u65f6\u949f\u6e90\u786c\u4ef6\u8bbe\u5907\u7684\u7cbe\u5ea6\u63d0\u9ad8\u548c\u8f6f\u4ef6\u9ad8\u7cbe\u5ea6\u8ba1\u65f6\u7684\u9700\u6c42\uff0c\u6709\u4e86\u9ad8\u7cbe\u5ea6\u65f6\u949f\u7684\u5185\u6838\u8bbe\u8ba1\u3002<\/p>\n
2\uff09\u9ad8\u7cbe\u5ea6\u65f6\u949f<\/p>\n
Linux 2.6.16 \uff0c\u5185\u6838\u652f\u6301\u4e86\u9ad8\u7cbe\u5ea6\u7684\u65f6\u949f\uff0c\u5185\u6838\u91c7\u7528\u65b0\u7684\u5b9a\u65f6\u5668hrtimer\uff0c\u5176\u5b9e\u73b0\u903b\u8f91\u548cLinux 2.6.16 \u4e4b\u524d\u5b9a\u65f6\u5668\u903b\u8f91\u533a\u522b\uff1a<\/p>\n
hrtimer\u91c7\u7528\u7ea2\u9ed1\u6811\u8fdb\u884c\u9ad8\u7cbe\u5ea6\u5b9a\u65f6\u5668\u7684\u7ba1\u7406\uff0c\u800c\u4e0d\u662f\u65f6\u95f4\u8f6e\uff1b<\/p>\n
\u9ad8\u7cbe\u5ea6\u65f6\u949f\u5b9a\u65f6\u5668\u4e0d\u5728\u4f9d\u8d56\u7cfb\u7edf\u7684tick\u4e2d\u65ad\uff0c\u800c\u662f\u57fa\u4e8e\u4e8b\u4ef6\u89e6\u53d1\u3002<\/p>\n
\u65e7\u5185\u6838\u7684\u5b9a\u65f6\u5668\u5b9e\u73b0\u4f9d\u8d56\u4e8e\u7cfb\u7edf\u5b9a\u65f6\u5668\u786c\u4ef6\u5b9a\u671f\u7684tick\uff0c\u57fa\u4e8e\u8be5tick\uff0c\u5185\u6838\u4f1a\u626b\u63cftimer wheel\u5904\u7406\u8d85\u65f6\u4e8b\u4ef6\uff0c\u4f1a\u66f4\u65b0jiffies\uff0cwall time(\u5899\u4e0a\u65f6\u95f4\uff0c\u73b0\u5b9e\u65f6\u95f4)\uff0cprocess\u7684\u4f7f\u7528\u65f6\u95f4\u7b49\u7b49\u5de5\u4f5c\u3002<\/p>\n
\u65b0\u7684\u5185\u6838\u4e0d\u518d\u4f1a\u76f4\u63a5\u652f\u6301\u5468\u671f\u6027\u7684tick\uff0c\u65b0\u5185\u6838\u5b9a\u65f6\u5668\u6846\u67b6\u91c7\u7528\u4e86\u57fa\u4e8e\u4e8b\u4ef6\u89e6\u53d1\uff0c\u800c\u4e0d\u662f\u4ee5\u524d\u7684\u5468\u671f\u6027\u89e6\u53d1\u3002\u65b0\u5185\u6838\u5b9e\u73b0\u4e86hrtimer(high resolution timer)\uff1a\u4e8e\u4e8b\u4ef6\u89e6\u53d1\u3002<\/p>\n
hrtimer\u7684\u5de5\u4f5c\u539f\u7406\uff1a<\/p>\n
\u901a\u8fc7\u5c06\u9ad8\u7cbe\u5ea6\u65f6\u949f\u786c\u4ef6\u7684\u4e0b\u6b21\u4e2d\u65ad\u89e6\u53d1\u65f6\u95f4\u8bbe\u7f6e\u4e3a\u7ea2\u9ed1\u6811\u4e2d\u6700\u65e9\u5230\u671f\u7684Timer \u7684\u65f6\u95f4\uff0c\u65f6\u949f\u5230\u671f\u540e\u4ece\u7ea2\u9ed1\u6811\u4e2d\u5f97\u5230\u4e0b\u4e00\u4e2a Timer \u7684\u5230\u671f\u65f6\u95f4\uff0c\u5e76\u8bbe\u7f6e\u786c\u4ef6\uff0c\u5982\u6b64\u5faa\u73af\u53cd\u590d\u3002<\/p>\n
\u5728\u9ad8\u7cbe\u5ea6\u65f6\u949f\u6a21\u5f0f\u4e0b\uff0c\u64cd\u4f5c\u7cfb\u7edf\u5185\u6838\u4ecd\u7136\u9700\u8981\u5468\u671f\u6027\u7684tick\u4e2d\u65ad\uff0c\u4ee5\u4fbf\u5237\u65b0\u5185\u6838\u7684\u4e00\u4e9b\u4efb\u52a1\u3002hrtimer\u662f\u57fa\u4e8e\u4e8b\u4ef6\u7684\uff0c\u4e0d\u4f1a\u5468\u671f\u6027\u51fa\u53d1tick\u4e2d\u65ad\uff0c\u6240\u4ee5\u4e3a\u4e86\u5b9e\u73b0\u5468\u671f\u6027\u7684tick\u4e2d\u65ad(dynamic tick)\uff1a\u7cfb\u7edf\u521b\u5efa\u4e86\u4e00\u4e2a\u6a21\u62df tick \u65f6\u949f\u7684\u7279\u6b8a hrtimer\uff0c\u5c06\u5176\u8d85\u65f6\u65f6\u95f4\u8bbe\u7f6e\u4e3a\u4e00\u4e2atick\u65f6\u957f\uff0c\u5728\u8d85\u65f6\u56de\u6765\u540e\uff0c\u5b8c\u6210\u5bf9\u5e94\u7684\u5de5\u4f5c\uff0c\u7136\u540e\u518d\u6b21\u8bbe\u7f6e\u4e0b\u4e00\u4e2atick\u7684\u8d85\u65f6\u65f6\u95f4\uff0c\u4ee5\u6b64\u8fbe\u5230\u5468\u671f\u6027tick\u4e2d\u65ad\u7684\u9700\u6c42\u3002<\/p>\n
\u5f15\u5165\u4e86dynamic tick\uff0c\u662f\u4e3a\u4e86\u80fd\u591f\u5728\u4f7f\u7528\u9ad8\u7cbe\u5ea6\u65f6\u949f\u7684\u540c\u65f6\u8282\u7ea6\u80fd\u6e90\uff0c\u8fd9\u6837\u4f1a\u4ea7\u751ftickless \u60c5\u51b5\u4e0b\uff0c\u4f1a\u8df3\u8fc7\u4e00\u4e9b tick\u3002<\/p>\n
\u65b0\u5185\u6838\u5bf9\u76f8\u5173\u7684\u65f6\u95f4\u786c\u4ef6\u8bbe\u5907\u8fdb\u884c\u4e86\u7edf\u4e00\u7684\u5c01\u88c5\uff0c\u5b9a\u4e49\u4e86\u4e3b\u8981\u6709\u4e0b\u9762\u4e24\u4e2a\u7ed3\u6784\uff1a<\/p>\n
\u65f6\u949f\u6e90\u8bbe\u5907(closk source device)\uff1a\u62bd\u8c61\u90a3\u4e9b\u80fd\u591f\u63d0\u4f9b\u8ba1\u65f6\u529f\u80fd\u7684\u7cfb\u7edf\u786c\u4ef6\uff0c\u6bd4\u5982 RTC(Real Time Clock)\u3001TSC(Time Stamp Counter)\uff0cHPET\uff0cACPI PM-Timer\uff0cPIT\u7b49\u3002\u4e0d\u540c\u65f6\u949f\u6e90\u63d0\u4f9b\u7684\u7cbe\u5ea6\u4e0d\u4e00\u6837\uff0c\u73b0\u5728pc\u5927\u90fd\u662f\u652f\u6301\u9ad8\u7cbe\u5ea6\u6a21\u5f0f(high-resolution mode)\u4e5f\u652f\u6301\u4f4e\u7cbe\u5ea6\u6a21\u5f0f(low-resolution mode)\u3002<\/p>\n
\u65f6\u949f\u4e8b\u4ef6\u8bbe\u5907(clock event device)\uff1a\u7cfb\u7edf\u4e2d\u53ef\u4ee5\u89e6\u53d1 one-shot\uff08\u5355\u6b21\uff09\u6216\u8005\u5468\u671f\u6027\u4e2d\u65ad\u7684\u8bbe\u5907\u90fd\u53ef\u4ee5\u4f5c\u4e3a\u65f6\u949f\u4e8b\u4ef6\u8bbe\u5907\u3002<\/p>\n
\u5f53\u524d\u5185\u6838\u540c\u65f6\u5b58\u5728\u65b0\u65e7timer wheel \u548c hrtimer\u4e24\u5957timer\u7684\u5b9e\u73b0\uff0c\u5185\u6838\u542f\u52a8\u540e\u4f1a\u8fdb\u884c\u4ece\u4f4e\u7cbe\u5ea6\u6a21\u5f0f\u5230\u9ad8\u7cbe\u5ea6\u65f6\u949f\u6a21\u5f0f\u7684\u5207\u6362\uff0chrtimer\u6a21\u62df\u7684tick\u4e2d\u65ad\u5c06\u9a71\u52a8\u4f20\u7edf\u7684\u4f4e\u7cbe\u5ea6\u5b9a\u65f6\u5668\u7cfb\u7edf\uff08\u57fa\u4e8e\u65f6\u95f4\u8f6e\uff09\u548c\u5185\u6838\u8fdb\u7a0b\u8c03\u5ea6\u3002<\/p>\n
<pre><code> "“`
\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
“`” \u53c2\u8003\u56de\u7b54\uff1a 1\uff09\u4f4e\u7cbe\u5ea6\u65f6\u949f Linux 2.6.16\u4e4b\u524d\uff0c\u5185\u6838\u53ea\u652f\u6301\u4f4e\u7cbe\u5ea6\u65f6\u949f […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-46913","post","type-post","status-publish","format-standard","hentry","category-c"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/46913","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=46913"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/46913\/revisions"}],"predecessor-version":[{"id":46914,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/46913\/revisions\/46914"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=46913"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=46913"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=46913"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}