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想找出占用cpu高的进程，用top命令就可以搞定。
$top.....此处省略n多行...10434 root 20 0 509m 174m 1528 R 99.7 0.5 8:42.43 php 5638 root 20 0 509m 174m 1528 R 99.1 0.5 9:12.35 php 16390 root 20 0 541m 182m 5244 R 98.4 0.6 8:40.92 php
此时，轻轻按下C键。就会看到如下信息。
10434 root 20 0 540m 182m 5244 R 101.0 0.6 9:57.39 php /home/gearman_manager/pecl-manager.php -P /home/gearman_manager/manager.pid -u root -d -v5638 root 20 0 509m 174m 1528 R 101.0 0.5 10:15.28 php /home/gearman_manager/pecl-manager.php -P /home/gearman_manager/manager.pid -u root -d -v16390 root 20 0 509m 174m 1528 R 99.5 0.5 9:41.18 php /home/gearman_manager/pecl-manager.php -P /home/gearman_manager/manager.pid -u root -d -vv
找出进程占用cpu高的原因
进程占用cpu高，一般是由于进程长时间占用cpu，又没有主动释放占用。如果想主动释放cpu，可以调用sleep。在写程序的时候，尤其要注意while 等循环的地方。找出php进程在执行那段代码
$sudo gdb -p 10434(gdb) print (char *)executor_globals.active_op_array->filename$13 = 0x2924118 "/home/gearman_manager/pecl-manager.php"(gdb) print executor_globals->current_execute_data->opline->lineno$14 = 55(gdb) cContinuing.^CProgram received signal SIGINT, Interrupt.0x00000031d32306d0 in sigprocmask () from /lib64/libc.so.6(gdb) print executor_globals->current_execute_data->opline->lineno$15 = 71(gdb) cContinuing.^CProgram received signal SIGINT, Interrupt.0x00000000006250e1 in zend_hash_find ()(gdb) print executor_globals->current_execute_data->opline->lineno$16 = 53
如果对上面的命令有疑问，可以查看 []
根据上面的信息，我们可以知道，cpu高时，正在执行/home/gearman_manager/pecl-manager.php文件。并且正在执行53和71行附近的代码。分析相关代码
php的相关代码如下：while(!$this->stop_work){ //此处是第51行 if(@$thisWorker->work() || $thisWorker->returnCode() == GEARMAN_IO_WAIT || $thisWorker->returnCode() == GEARMAN_NOT_CONNECTED || $thisWorker->returnCode() == GEARMAN_NO_JOBS) { if ($thisWorker->returnCode() == GEARMAN_SUCCESS) continue; if (!@$thisWorker->wait()){ if ($thisWorker->returnCode() == GEARMAN_NO_ACTIVE_FDS){ sleep(5); } } } /** * Check the running time of the current child. If it has * been too long, stop working. */ //此处是第71行 if($this->max_run_time > 0 && time() - $start > $this->max_run_time) { $this->log("Been running too long, exiting", GearmanManager::LOG_LEVEL_WORKER_INFO); $this->stop_work = true; } if(!empty($this->config["max_runs_per_worker"]) && $this->job_execution_count >= $this->config["max_runs_per_worker"]) { $this->log("Ran $this->job_execution_count jobs which is over the maximum({$this->config['max_runs_per_worker']}), exiting", GearmanManager::LOG_LEVEL_WORKER_INFO); $this->stop_work = true; } } 看来作者已经考虑到某些情况可能导致cpu 100，因此在代码中使用了sleep方法。现在php进程占用cpu 100，看来是没执行sleep(5)。如果$thisWorker->work() 和 $thisWorker->returnCode() 方法中没有IO等操作，能释放cpu的占用，又没有调用sleep的情况下，很容易导致进程占用cpu 100。
根据代码我们可以得出如下几个结论： - 肯定没执行slepp(5) - $thisWorker->work() 和 $thisWorker->returnCode() 方法中没有IO等操作，能释放cpu的占用。进一步跟踪代码中可疑部分
分析 $thisWorker->returnCode() 的返回值。如果很容易复现cpu 100的话，你可以在程序中echo $thisWorker->returnCode() 来获得返回值。但是现在cpu 100的问题，复现比较麻烦。所以，还是使用gdb 来搞吧。$gdb -p 10434(gdb)b zif_gearman_worker_return_code Breakpoint 1, zif_gearman_worker_return_code (ht=0, return_value=0x2a1b648, return_value_ptr=0x0, this_ptr=0x2a14090, return_value_used=1) at /home/php_src/pecl/gearman-1.1.1/php_gearman.c:31863186 in /home/php_src/pecl/gearman-1.1.1/php_gearman.c(gdb) p return_value$3 = (zval *) 0x2a1b648(gdb) p *$3$4 = {value = {lval = 0, dval = 0, str = {val = 0x0, len = 0}, ht = 0x0, obj = {handle = 0, handlers = 0x0}}, refcount__gc = 1, type = 0 '\0', is_ref__gc = 0 '\0'}(gdb) s3189 in /home/php_src/pecl/gearman-1.1.1/php_gearman.c(gdb) p *$3$5 = {value = {lval = 0, dval = 0, str = {val = 0x0, len = 0}, ht = 0x0, obj = {handle = 0, handlers = 0x0}}, refcount__gc = 1, type = 0 '\0', is_ref__gc = 0 '\0'}(gdb) s3186 in /home/php_src/pecl/gearman-1.1.1/php_gearman.c(gdb) p *$3$6 = {value = {lval = 0, dval = 0, str = {val = 0x0, len = 0}, ht = 0x0, obj = {handle = 0, handlers = 0x0}}, refcount__gc = 1, type = 0 '\0', is_ref__gc = 0 '\0'}(gdb) s3189 in /home/php_src/pecl/gearman-1.1.1/php_gearman.c(gdb) p *$3$7 = {value = {lval = 0, dval = 0, str = {val = 0x0, len = 0}, ht = 0x0, obj = {handle = 0, handlers = 0x0}}, refcount__gc = 1, type = 0 '\0', is_ref__gc = 0 '\0'}(gdb) s3190 in /home/php_src/pecl/gearman-1.1.1/php_gearman.c(gdb) p *$3$8 = {value = {lval = 0, dval = 0, str = {val = 0x0, len = 0}, ht = 0x0, obj = {handle = 0, handlers = 0x0}}, refcount__gc = 1, type = 0 '\0', is_ref__gc = 0 '\0'}(gdb) s3191 in /home/php_src/pecl/gearman-1.1.1/php_gearman.c(gdb) p *$3$9 = {value = {lval = 25, dval = 1.2351641146031164e-322, str = {val = 0x19 , len = 0}, ht = 0x19, obj = {handle = 25, handlers = 0x0}}, refcount__gc = 1, type = 1 '\001', is_ref__gc = 0 '\0'} 从最后的lval = 25 和 type =1 我们可以看出 returnCode()方法的最后返回值是 25 。 根据文档，返回值25 对应的是 GEARMAN_NOT_CONNECTED。 ## 解决问题 既然出问题时， returnCode()方法的最后返回值是 25，而现在程序中对这种情况又没进行出来，导致了cpu 100。那我们只要在出现这种情况时，sleep几秒就ok了。 if(@$thisWorker->work() || $thisWorker->returnCode() == GEARMAN_IO_WAIT || $thisWorker->returnCode() == GEARMAN_NOT_CONNECTED || $thisWorker->returnCode() == GEARMAN_NO_JOBS) { //下面一行是新增的 if ($thisWorker->returnCode() == GEARMAN_NOT_CONNECTED) sleep(5); if ($thisWorker->returnCode() == GEARMAN_SUCCESS) continue; if (!@$thisWorker->wait()){ if ($thisWorker->returnCode() == GEARMAN_NO_ACTIVE_FDS){ sleep(5); } } } 转载地址：http://nucgo.baihongyu.com/