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authorTao Zhou <ouwen210@hotmail.com>2020-07-24 04:47:42 +0200
committerJonathan Corbet <corbet@lwn.net>2020-07-28 00:32:27 +0200
commite210c66d567c6dbd6b29bc89dc72b5327909bab1 (patch)
treed220ecc1d56085ca1047d0b9797a107054fdbd83
parentDocumentation/admin-guide: tainted-kernels: fix spelling mistake (diff)
downloadlinux-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.rst105
-rw-r--r--Documentation/translations/zh_CN/admin-guide/index.rst2
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