{"id":343248,"date":"2021-02-16T13:01:02","date_gmt":"2021-02-16T05:01:02","guid":{"rendered":"http:\/\/4563.org\/?p=343248"},"modified":"2021-02-16T13:01:02","modified_gmt":"2021-02-16T05:01:02","slug":"%e4%bd%bf%e7%94%a8-perf-%e8%bf%9b%e8%a1%8c%e7%a8%8b%e5%ba%8f%e7%83%ad%e7%82%b9%e5%88%86%e6%9e%90","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=343248","title":{"rendered":"\u4f7f\u7528 Perf \u8fdb\u884c\u7a0b\u5e8f\u70ed\u70b9\u5206\u6790"},"content":{"rendered":"<div>\n<div>\n<div>\n<h1>                  \u4f7f\u7528 Perf \u8fdb\u884c\u7a0b\u5e8f\u70ed\u70b9\u5206\u6790               <\/h1>\n<p> <\/p>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : PolyQY <\/span>  <span><i><\/i> 2<\/span> <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div isfirst=\"1\"> <\/p>\n<p>\u539f\u6587\u53d1\u5e03\u5728Easton Man&#8217;s Blog<\/p>\n<p>Perf \u662f\u4e00\u4e2a\u6027\u80fd\u5206\u6790\u5de5\u5177\uff0c\u81ea\u4ece Linux 2.6.31 \uff08 2009 \u5e74\uff09\u4ee5\u6765\u5c31\u88ab\u52a0\u5165\u4e86\u5185\u6838\u3002\u5b83\u5229\u7528\u5185\u6838\u8fd0\u884c\u65f6\u63d2\u6869\u7684\u65b9\u5f0f\u68c0\u6d4b\u7a0b\u5e8f\u7684\u8fd0\u884c\uff0c\u53ef\u4ee5\u63d0\u4f9b\u76f8\u5f53\u4e30\u5bcc\u7684\u4fe1\u606f\uff0c\u8db3\u4ee5\u8ba9\u6211\u4eec\u627e\u5230\u7a0b\u5e8f\u8fd0\u884c\u4e2d\u7684\u6027\u80fd\u74f6\u9888\u548c\u4f18\u5316\u91cd\u70b9\u3002<\/p>\n<h2>\u5b89\u88c5<\/h2>\n<p>\u5728\u67d0\u4e9b\u7cfb\u7edf\u4e2d\u53ef\u80fd\u6709\u9884\u88c5\u5b8c\u6574\u7684 Perf\uff0c\u4f46\u662f\u5728\u6211\u6240\u4f7f\u7528\u7684 Debian Buster \uff08 10 \uff09\u4e0a\uff0c\u53ea\u6709\u7528\u6237\u7a7a\u95f4\u7684\u7a0b\u5e8f\u88ab\u9884\u88c5\u4e86\uff0c\u6240\u4ee5\u8fd8\u9700\u5b89\u88c5\u5bf9\u5e94\u7684\u5185\u6838\u5de5\u5177\u3002\u901a\u5e38\u6765\u8bf4\uff0c\u4ee5\u4e0b\u7684\u8fd9\u4e00\u6761\u547d\u4ee4\u53ef\u4ee5\u5b89\u88c5\u5bf9\u5e94\u5185\u6838\u7248\u672c\u7684 Perf \u5185\u6838\u90e8\u5206\u3002\u4f46\u662f\u5982\u679c\u6b64\u65f6\u6b63\u5728\u4f7f\u7528\u7684\u5185\u6838\u4e0d\u662f apt \u4e2d\u6700\u65b0\u7684\u5185\u6838\uff0c\u5219\u9700\u8981\u91cd\u542f\u4ee5\u5207\u6362\u5230\u65b0\u7684\u5185\u6838\uff0c\u6216\u8005\u5b89\u88c5\u6307\u5b9a\u7248\u672c\u7684 Perf \u5185\u6838\u5de5\u5177\u3002<\/p>\n<pre><code>sudo apt install linux-perf sudo apt install linux-perf-5.8 # \u6307\u5b9a\u5185\u6838\u7248\u672c <\/code><\/pre>\n<p>\u6b64\u65f6\u6211\u4eec\u5e94\u8be5\u5df2\u7ecf\u53ef\u4ee5\u8fd0\u884c perf \u4e86\uff0c\u4f46\u662f\u901a\u5e38\u4f1a\u51fa\u73b0\u4ee5\u4e0b\u7684\u7ed3\u679c\uff1a<\/p>\n<pre><code>$&gt; perf record Error: You may not have permission to collect stats. Consider tweaking \/proc\/sys\/kernel\/perf_event_paranoid:  -1 - Not paranoid at all   0 - Disallow raw tracepoint access for unpriv   1 - Disallow cpu events for unpriv   2 - Disallow kernel profiling for unpriv <\/code><\/pre>\n<p>\u6216\u8005\u8bf4\u8fd9\u6837<\/p>\n<pre><code>Plain text Error: Access to performance monitoring and observability operations is limited. Consider adjusting \/proc\/sys\/kernel\/perf_event_paranoid setting to open access to performance monitoring and observability operations for processes without CAP_PERFMON, CAP_SYS_PTRACE or CAP_SYS_ADMIN Linux capability. More information can be found at 'Perf events and tool security' document: https:\/\/www.kernel.org\/doc\/html\/latest\/admin-guide\/perf-security.html perf_event_paranoid setting is 3:   -1: Allow use of (almost) all events by all users       Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK &gt;= 0: Disallow raw and ftrace function tracepoint access &gt;= 1: Disallow CPU event access &gt;= 2: Disallow kernel profiling To make the adjusted perf_event_paranoid setting permanent preserve it in \/etc\/sysctl.conf (e.g. kernel.perf_event_paranoid = &lt;setting&gt;) <\/code><\/pre>\n<p>\u8fd9\u662f\u56e0\u4e3a\u51fa\u4e8e\u5b89\u5168\u8003\u8651\uff0c\u5185\u6838\u5728\u9ed8\u8ba4\u60c5\u51b5\u4e0b\u7981\u6b62\u975e\u7279\u6743\u7528\u6237\u76d1\u6d4b\u7cfb\u7edf\u6027\u80fd\u3002\u89e3\u51b3\u7684\u529e\u6cd5\u6709\u4ee5\u4e0b\u51e0\u79cd\uff1a<\/p>\n<ul>\n<li>\u4fee\u6539 kernel.perf_event_paranoid \u5185\u6838\u53c2\u6570<\/li>\n<li>\u7ed9 perf \u52a0\u5165 CAP_PERFMON \u6743\u9650\u4f4d<\/li>\n<li>\u4f7f\u7528 root \u7528\u6237\u8fdb\u884c\u6027\u80fd\u76d1\u6d4b<\/li>\n<\/ul>\n<p>\u6211\u81ea\u5df1\u4e00\u822c\u4f7f\u7528\u7b2c\u4e00\u79cd\uff0c\u56e0\u6b64\u4ecb\u7ecd\u7b2c\u4e00\u79cd\u65b9\u6cd5\u7684\u8be6\u7ec6\u505a\u6cd5\u3002\u4e0d\u63a8\u8350\u4f7f\u7528 root \u7528\u6237\u8fd0\u884c perf\uff0c\u56e0\u4e3a\u8fd9\u6837\u53ef\u80fd\u4f1a\u6709\u5b89\u5168\u9690\u60a3\u3002<\/p>\n<p>\u4fee\u6539 kernel.perf_event_paranoid \u53c2\u6570\u6709\u4e24\u79cd\u505a\u6cd5\u3002\u7b2c\u4e00\u79cd\u65b9\u6cd5\u662f\u4e34\u65f6\u7684\uff0c\u91cd\u542f\u540e\u5c31\u5931\u6548\u4e86\uff0c\u4f46\u662f\u5feb\u901f\u4e00\u70b9<\/p>\n<pre><code>sudo sh -c \"echo -1 &gt; \/proc\/sys\/kernel\/perf_event_paranoid\" <\/code><\/pre>\n<p>\u6216\u8005\u4f7f\u7528 sysctl \u547d\u4ee4<\/p>\n<pre><code>sudo sysctl -w kernel.perf_event_paranoid=-1 EnlighterJS Syntax Highlighter \u7b2c\u4e8c\u79cd\u65b9\u6cd5\u662f\u4fee\u6539 sysctl \u7684\u914d\u7f6e\u6587\u4ef6\uff0c\u5728\u6211\u7684\u73af\u5883\u4e2d\uff0c\u8fd9\u4e2a\u6587\u4ef6\u4f4d\u4e8e \/etc\/sysctl.conf\uff0c\u6709\u7684\u7cfb\u7edf\u4e2d\u4f1a\u4f7f\u7528 \/etc\/sysctl.d Generic Highlighting sudo sh -c 'echo \"kernel.perf_event_paranoid=-1\" &gt;&gt; \/etc\/sysctl.conf' sudo sysctl -p <\/code><\/pre>\n<p>\u8fd9\u6837\u64cd\u4f5c\u5b8c\u6210\u4ee5\u540e\uff0c\u5185\u6838\u5c31\u4f1a\u5141\u8bb8\u975e\u7279\u6743\u7528\u6237\u4f7f\u7528 perf \u5185\u6838\u90e8\u5206\u4e2d\u7684\u63a5\u53e3\u4e86\u3002<\/p>\n<h2>\u4f7f\u7528<\/h2>\n<p>perf \u6709\u51e0\u79cd\u5e38\u7528\u7684\u4f7f\u7528\u65b9\u5f0f\uff0c\u7b2c\u4e00\u79cd\u662f\u8f83\u4e3a\u7b80\u5355\u7684\u7c97\u7565\u4e86\u89e3\u7a0b\u5e8f\u4f7f\u7528\u786c\u4ef6\u7684\u60c5\u51b5<\/p>\n<pre><code>$&gt; perf stat ls  &lt;stdout&gt;  Performance counter stats for 'ls':                1.87 msec task-clock                #    0.411 CPUs utilized                 11      context-switches          #    0.006 M\/sec                  0      cpu-migrations            #    0.000 K\/sec                 94      page-faults               #    0.050 M\/sec          2,771,746      cycles                    #    1.479 GHz          1,534,926      instructions              #    0.55  insn per cycle            317,631      branches                  #  169.519 M\/sec             15,169      branch-misses             #    4.78% of all branches         0.004553499 seconds time elapsed         0.003498000 seconds user        0.000000000 seconds sys <\/code><\/pre>\n<p>\u7b2c\u4e8c\u79cd\u4e5f\u662f\u529f\u80fd\u5f3a\u5927\u7684\u4e00\u79cd\uff0c\u53ef\u4ee5\u8be6\u7ec6\u5206\u6790\u7a0b\u5e8f\u5404\u51fd\u6570\u7684\u8fd0\u884c\u65f6\u95f4\u5360\u6bd4\uff0c\u8fd8\u53ef\u4ee5\u67e5\u770b\u8fd9\u4e9b\u51fd\u6570\u4e2d\u5404\u4e2a\u6307\u4ee4\u7684\u8017\u65f6\u5360\u6bd4\uff0c\u8fd9\u4f7f\u5f97\u6211\u4eec\u53ef\u4ee5\u7cbe\u786e\u5730\u4e86\u89e3\u7a0b\u5e8f\u8fd0\u884c\u65f6\u7684\u74f6\u9888\u7684\u5904\u7406\u5668\u8d44\u6e90\u4f7f\u7528\u60c5\u51b5\u3002<\/p>\n<pre><code>perf record &lt;program&gt; perf report <\/code><\/pre>\n<p>\u8fd9\u65f6\u6211\u4eec\u5c31\u53ef\u4ee5\u770b\u5230\u7c7b\u4f3c\u8fd9\u6837\u7684\u754c\u9762<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" referrerpolicy=\"no-referrer\" rel=\"noreferrer\" src=\"http:\/\/4563.org\/wp-content\/uploads\/2021\/02\/20210219_602fe611d52f4.png\" alt=\"\u4f7f\u7528 Perf \u8fdb\u884c\u7a0b\u5e8f\u70ed\u70b9\u5206\u6790\" \/> \u6b64\u65f6\u6309\u4e0b A \u53ef\u4ee5\u770b\u5230\u53cd\u6c47\u7f16\u540e\u7684\u6c47\u7f16\u4ee3\u7801\u548c\u76f8\u5e94\u7684\u65f6\u95f4\u5360\u6bd4\u3002<\/p>\n<p>\u6709\u7684\u65f6\u5019\u5982\u679c\u7f16\u8bd1\u65f6\u5173\u95ed\u4e86 debug \u9009\u9879\uff08\u5982 gcc -g \uff09\u90a3\u4e48 perf \u5f88\u53ef\u80fd\u4e0d\u80fd\u5f97\u5230\u6b63\u786e\u7684\u8c03\u7528\u6808\uff0c\u8fd9\u6837\u65f6\u95f4\u5360\u6bd4\u7684\u7edf\u8ba1\u5c31\u4f1a\u6709\u95ee\u9898\uff0c\u4e0d\u5229\u4e8e\u6211\u4eec\u89c2\u5bdf\u70ed\u70b9\u51fd\u6570\uff0c\u6b64\u65f6\u53ef\u4ee5\u6307\u5b9a perf \u4f7f\u7528\u66f4\u8be6\u7ec6\u7684\u8c03\u7528\u6808\u8ddf\u8e2a\u65b9\u6cd5\uff0c\u4f8b\u5982\u4f7f\u7528 lbr<\/p>\n<pre><code>perf record --call-graph lbr &lt;program&gt; <\/code><\/pre>\n<p>perf \u53ef\u4ee5\u4f7f\u7528\u7684\u8c03\u7528\u6808\u8ddf\u8e2a\u65b9\u6cd5\u6709\u4e09\u79cd\uff1a<\/p>\n<ul>\n<li>fp\uff1a\u6700\u4e0d\u8be6\u7ec6\uff0c\u4ea7\u751f\u7684\u8bb0\u5f55\u6587\u4ef6\u4e5f\u6700\u5c0f\uff0c\u5bf9\u7a0b\u5e8f\u7684\u6027\u80fd\u51e0\u4e4e\u65e0\u5f71\u54cd\u3002<\/li>\n<li>lbr\uff1a\u8f83\u4e3a\u8be6\u7ec6\uff0c\u4ea7\u751f\u7684\u8bb0\u5f55\u6587\u4ef6\u663e\u8457\u589e\u5927\uff0c\u5bf9\u7a0b\u5e8f\u7684\u6027\u80fd\u6709\u5c11\u91cf\u7684\u5f71\u54cd\u3002<\/li>\n<li>dwarf\uff1a\u6700\u8be6\u7ec6\uff0c\u4ea7\u751f\u7684\u8bb0\u5f55\u6587\u4ef6\u6781\u5176\u5de8\u5927\uff0c1 \u5206\u949f\u53ef\u80fd\u80fd\u8bb0\u5f55 10G\uff0c\u5bf9\u7a0b\u5e8f\u6027\u80fd\u6709\u663e\u8457\u5f71\u54cd\uff0c\u56e0\u6b64\u5e76\u4e0d\u5f88\u5b9e\u7528\u3002 \u5bf9\u6211\u6765\u8bf4\u4e00\u822c\u76f4\u63a5\u9009\u62e9 lbr \u5c31\u53ef\u4ee5\u4e86\uff0c\u5982\u679c\u786c\u76d8\u4e0d\u591f\u5927\u6216\u8005\u8bfb\u5199\u51e0\u4e2a G \u7684\u6587\u4ef6\u5f88\u6162\u7684\u8bdd\u518d\u8003\u8651 fp \u3002<\/li>\n<\/ul>\n<p>\u8fd9\u51e0\u79cd\u8c03\u7528\u6808\u8ddf\u8e2a\u65b9\u5f0f\u7684\u8be6\u7ec6\u533a\u522b\u53ef\u4ee5\u53c2\u8003\u5927\u795e\u535a\u5ba2<\/p>\n<h2>\u6df1\u5165\u9605\u8bfb<\/h2>\n<p>Investigating Linux Performance with Off-CPU Flame Graphs<\/p>\n<p>Linux eBPF Off-CPU Flame Graph<\/p>\n<p>FlameGraph<\/p>\n<\/p><\/div>\n<div> <b>\u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (<span>1<\/span>)        <\/div>\n<div> <\/div>\n<\/p><\/div>\n<\/p><\/div>\n<ul>\n<li data-pid=\"5284050\" data-uid=\"2\">\n<div>\n<div>\n<div> <span>\u8cc7\u6df1\u5927\u4f6c : liuguangxuan <\/span>  <\/div>\n<div> <i title=\"\u5f15\u7528\"><\/i>  <span>          <\/span> <\/div>\n<\/p><\/div>\n<div>                                                             \u4f60\u8fd9\u662f\u5728\u5e72\u5565                                                            <\/div>\n<\/p><\/div>\n<\/li>\n<li>\n","protected":false},"excerpt":{"rendered":"<p>\u4f7f\u7528 Perf \u8fdb\u884c\u7a0b\u5e8f\u70ed\u70b9\u5206\u6790 &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/343248"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=343248"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/343248\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=343248"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=343248"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=343248"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}