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author | Tao Zhou <ouwen210@hotmail.com> | 2020-07-24 04:47:42 +0200 |
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committer | Jonathan Corbet <corbet@lwn.net> | 2020-07-28 00:32:27 +0200 |
commit | e210c66d567c6dbd6b29bc89dc72b5327909bab1 (patch) | |
tree | d220ecc1d56085ca1047d0b9797a107054fdbd83 | |
parent | Documentation/admin-guide: tainted-kernels: fix spelling mistake (diff) | |
download | linux-e210c66d567c6dbd6b29bc89dc72b5327909bab1.tar.xz linux-e210c66d567c6dbd6b29bc89dc72b5327909bab1.zip |
doc/zh_CN: add cpu-load Chinese version
Add cpu-load Chinese version and link it into admin-guide.
Based on Alex's recent thread:
https://lkml.kernel.org/r/20200713115807.56362-1-alex.shi@linux.alibaba.com
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Tao Zhou <ouwen210@hotmail.com>
Link: https://lore.kernel.org/r/BL0PR14MB37798BBF2307910DE73EF6D49A770@BL0PR14MB3779.namprd14.prod.outlook.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
-rw-r--r-- | Documentation/translations/zh_CN/admin-guide/cpu-load.rst | 105 | ||||
-rw-r--r-- | Documentation/translations/zh_CN/admin-guide/index.rst | 2 |
2 files changed, 106 insertions, 1 deletions
diff --git a/Documentation/translations/zh_CN/admin-guide/cpu-load.rst b/Documentation/translations/zh_CN/admin-guide/cpu-load.rst new file mode 100644 index 000000000000..0116d0477799 --- /dev/null +++ b/Documentation/translations/zh_CN/admin-guide/cpu-load.rst @@ -0,0 +1,105 @@ +======= +CPU 负载 +======= + +Linux通过``/proc/stat``和``/proc/uptime``导出各种信息,用户空间工具 +如top(1)使用这些信息计算系统花费在某个特定状态的平均时间。 +例如: + + $ iostat + Linux 2.6.18.3-exp (linmac) 02/20/2007 + + avg-cpu: %user %nice %system %iowait %steal %idle + 10.01 0.00 2.92 5.44 0.00 81.63 + + ... + +这里系统认为在默认采样周期內有10.01%的时间工作在用户空间,2.92%的时 +间用在系统空间,总体上有81.63%的时间是空闲的。 + +大多数情况下``/proc/stat``的信息几乎真实反映了系统信息,然而,由于内 +核采集这些数据的方式/时间的特点,有时这些信息根本不可靠。 + +那么这些信息是如何被搜集的呢?每当时间中断触发时,内核查看此刻运行的 +进程类型,并增加与此类型/状态进程对应的计数器的值。这种方法的问题是 +在两次时间中断之间系统(进程)能够在多种状态之间切换多次,而计数器只 +增加最后一种状态下的计数。 + +举例 +--- + +假设系统有一个进程以如下方式周期性地占用cpu:: + + 两个时钟中断之间的时间线 + |-----------------------| + ^ ^ + |_ 开始运行 | + |_ 开始睡眠 + (很快会被唤醒) + +在上面的情况下,根据``/proc/stat``的信息(由于当系统处于空闲状态时, +时间中断经常会发生)系统的负载将会是0 + +大家能够想象内核的这种行为会发生在许多情况下,这将导致``/proc/stat`` +中存在相当古怪的信息:: + + /* gcc -o hog smallhog.c */ + #include <time.h> + #include <limits.h> + #include <signal.h> + #include <sys/time.h> + #define HIST 10 + + static volatile sig_atomic_t stop; + + static void sighandler (int signr) + { + (void) signr; + stop = 1; + } + static unsigned long hog (unsigned long niters) + { + stop = 0; + while (!stop && --niters); + return niters; + } + int main (void) + { + int i; + struct itimerval it = { .it_interval = { .tv_sec = 0, .tv_usec = 1 }, + .it_value = { .tv_sec = 0, .tv_usec = 1 } }; + sigset_t set; + unsigned long v[HIST]; + double tmp = 0.0; + unsigned long n; + signal (SIGALRM, &sighandler); + setitimer (ITIMER_REAL, &it, NULL); + + hog (ULONG_MAX); + for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog (ULONG_MAX); + for (i = 0; i < HIST; ++i) tmp += v[i]; + tmp /= HIST; + n = tmp - (tmp / 3.0); + + sigemptyset (&set); + sigaddset (&set, SIGALRM); + + for (;;) { + hog (n); + sigwait (&set, &i); + } + return 0; + } + + +参考 +--- + +- http://lkml.org/lkml/2007/2/12/6 +- Documentation/filesystems/proc.rst (1.8) + + +谢谢 +--- + +Con Kolivas, Pavel Machek diff --git a/Documentation/translations/zh_CN/admin-guide/index.rst b/Documentation/translations/zh_CN/admin-guide/index.rst index 76637ff880c5..7d502fa5da64 100644 --- a/Documentation/translations/zh_CN/admin-guide/index.rst +++ b/Documentation/translations/zh_CN/admin-guide/index.rst @@ -55,6 +55,7 @@ Todolist: :maxdepth: 1 clearing-warn-once + cpu-load Todolist: @@ -71,7 +72,6 @@ Todolist: cgroup-v1/index cgroup-v2 cifs/index - cpu-load cputopology dell_rbu device-mapper/index |