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Android中logcat和日志打印

2022年07月19日25yxwkf

 一、logcat对日志过滤

1.# logcat --help

# logcat --help 
Usage: logcat [options] [filterspecs] 
options include: 
  -s              Set default filter to silent. 
                  Like specifying filterspec '*:s' 
  -f <filename>   Log to file. Default to stdout 
  -r [<kbytes>]   Rotate log every kbytes. (16 if unspecified). Requires -f 
  -n <count>      Sets max number of rotated logs to <count>, default 4 
  -v <format>     Sets the log print format, where <format> is one of: 
 
                  brief process tag thread raw time threadtime long 
 
  -c              clear (flush) the entire log and exit 
  -d              dump the log and then exit (don't block) 
  -t <count>      print only the most recent <count> lines (implies -d) 
  -t '<time>'     print most recent lines since specified time (implies -d) 
  -T <count>      print only the most recent <count> lines (does not imply -d) 
  -T '<time>'     print most recent lines since specified time (not imply -d) 
                  count is pure numerical, time is 'MM-DD hh:mm:ss.mmm' 
  -g              get the size of the log's ring buffer and exit 
  -b <buffer>     Request alternate ring buffer, 'main', 'system', 'radio', 
                  'events', 'crash' or 'all'. Multiple -b parameters are 
                  allowed and results are interleaved. The default is 
                  -b main -b system -b crash. 
  -B              output the log in binary. 
  -S              output statistics. 
  -G <size>       set size of log ring buffer, may suffix with K or M. 
  -p              print prune white and ~black list. Service is specified as 
                  UID, UID/PID or /PID. Weighed for quicker pruning if prefix 
                  with ~, otherwise weighed for longevity if unadorned. All 
                  other pruning activity is oldest first. Special case ~! 
                  represents an automatic quicker pruning for the noisiest 
                  UID as determined by the current statistics. 
  -P '<list> ...' set prune white and ~black list, using same format as 
                  printed above. Must be quoted. 
 
filterspecs are a series of  
  <tag>[:priority] 
 
where <tag> is a log component tag (or * for all) and priority is: 
  V    Verbose (优先级最低) 
  D    Debug 
  I    Info 
  W    Warn 
  E    Error 
  F    Fatal 
  S    Silent (supress all output) (最高优先级,不会打印任何内容) 
 
'*' means '*:d' and <tag> by itself means <tag>:v 
 
If not specified on the commandline, filterspec is set from ANDROID_LOG_TAGS. 
If no filterspec is found, filter defaults to '*:I' 
 
If not specified with -v, format is set from ANDROID_PRINTF_LOG 
or defaults to "brief"

1. logcat命令位置:/system/bin/logcat

2.logcat的常用用法

# logcat -s <tag> 只看指定tag的log,还可以 logcat -s <tag1> -s <tag2> ... 过滤多个tag的log。

# logcat *:W 过滤日志则会将该级别及以上的日志输出

# logcat ActivityManager:I MyApp:D *:S 表示输出tag=“ActivityManager”的Info以上级别日志,输出tag=“MyApp”的Debug以上级别日志,及其它tag的Silent级别日志(即屏蔽其它 tag 日志)。

# logcat -d logcat应该是动态打印的,加-d后打印完log后退出,不阻塞
# logcat -t 20 只打印最近的20行log,-T也是类似的功能,但是打印完后不退出。
# logcat -f a.txt -f保存到文件中,不使用重定向符号的
# logcat | grep -i myapp 忽略大小写。
# logcat | grep --color=auto -i priv-app 匹配到的“priv-app”会显示出颜色
# logcat | grep --color=auto 1979 只打印出进程PID为1979的log
# logcat -c && logcat
# logcat -v time 打印时加上时间
# logcat -g 打印各个环形缓冲区的大小后退出
# logcat -S 打印出统计信息
# logcat | grep -E "Theft|u-blox" grep -E 正则表达式,可以一次性检索多个关键字
# logcat <tag1>:<priority1> <tag2>:<priority2> 过滤低优先级的日志

# logcat *:E   只查看错误打印

3.有 3 种方式使用 logcat 打印日志:
可以通过 IDE(比如 Android Studio)提供的 logcat 窗口查看打印的日志
可以通过 adb 命令使用 logcat 在本地计算机进行日志查看
通过 adb 命令进入模拟器或者所连设备的 shell 命令窗口,进行 logcat 的操作和使用

4.设置输出日志等级
通过设置优先级,过滤掉低优先级的日志,使用方式如: adb logcat <tag1>:<priority1> <tag2>:<priority2>
示例: logcat PowerManagerService:I PackageManager:I 表示logcat时不打印PowerManagerService和PackageManager的优先级低于Info的log

5.logcat选择打印的缓冲区:
# logcat -b <buffer> 可以指定要打印的环缓冲区,“main”,“system”,“radio”或“events”。 允许多个-b连用,这样打印的结果是交错的,默认为: -b main -b system -b crash。
radio - 查看缓冲区的相关的信息.
events - 查看和事件相关的的缓冲区.
main - 查看主要的日志缓冲区.
system - 与系统相关的日志信息.

6. logcat默认的几种输出格式为

格式:logcat -v threadtime

(1)brief格式为:<priority>/<tag>(<pid>): <message>  eg: D/HeadsetStateMachine( 1785): Disconnected process message: 10, size: 0

(2)process格式为:<priority>(<pid>) <message>  eg: D( 1785) Disconnected process message: 10, size: 0 (HeadsetStateMachine)

(3)tag格式为:<priority>/<tag>: <message>  eg: D/HeadsetStateMachine: Disconnected process message: 10, size: 0

(4)raw格式为:<message>   eg: Disconnected process message: 10, size: 0

(5)time格式为:<datetime> <priority>/<tag>(<pid>): <message>  eg: 08-28 22:39:39.974 D/HeadsetStateMachine( 1785): Disconnected process message: 10, size: 0

(6)threadtime格式为:<datetime> <pid> <tid> <priority> <tag>: <message>  eg: 08-28 22:39:39.974 1785 1832 D HeadsetStateMachine: Disconnected process message: 10, size: 0

(7)long格式为:[ <datetime> <pid>:<tid> <priority>/<tag> ] <message>  eg: [ 08-28 22:39:39.974 1785: 1832 D/HeadsetStateMachine ] Disconnected process  message: 10, size: 0

二、日志打印函数

1.程序中使用ALOGx(),SLOGx(),RLOGx()来分别打印app,system,radio的log,

x表示下面6种打印级别:
V Verbose
D Debug
I Info
W Warn
E Error
F Fatal

比如:
#define LOG_TAG "LedHal"
ALOGI("hal_led_ioctl called: which=%d, status=%d", which, status);
打印如下:

I/LedHal ( 2284): hal_led_ioctl called: which=0, status=0 //打印等级/Tag (PID): message

三、日志统计

1.# logcat -b all -S 可以统计出各个log buffer中最健谈的log的进程、UID、TAG

# logcat -b all -S 
size/num main               radio              events             system             crash  stats    performance   security           kernel             Total 
Total    4294940/52209      1224624/6903       386275/3669        1197331/12884      165/3   0/0     9132/180      0/0                0/0                7112467/75848 
Now      261517/3561        257987/1383        252696/2824        246225/2728        165/3           9132/180                                            1027722/10679 
Logspan  1:09:38.987(3.9%)  2:15:44.731(24.2%) 2:15:41.166(96.9%) 2:15:44.791(37%)   3:03.21         2:10:35.716                                         2:15:48.058 
Overhead 460933             335435             410840             398993             333             19212                                               1775074 
update time=0, report time=0, buffer rate = 0 Byte/sec, log rate = 0 sec-1 
buffer chatty rate = 15000 Byte/sec, log chatty rate = 100 sec-1 
 
最健谈的main log: 
Chattiest UIDs in main log buffer:                           Size   +/-  Pruned 
UID   PACKAGE                                               BYTES           NUM 
10061 com.android.systemui                                  51486  -14%    1256 
1000  system                                                40438  -67%    3478 
  PID/UID   COMMAND LINE                                       "             " 
 1612/1000  system_server                                    5384          2409 
 2972/1000  com.coloros.persist.system                       2999           623 
 
 
最健谈的main log: 
Chattiest UIDs in radio log buffer:                          Size   +/-  Pruned 
UID   PACKAGE                                               BYTES           NUM 
1001  radio                                                246546  -3.6%   5766 
1000  system                                                11037  5.2X 
 
 
最健谈的event log: 
Chattiest UIDs in events log buffer:                         Size   +/-  Pruned 
UID   PACKAGE                                               BYTES           NUM 
1000  system                                               231850  +4.3%    260 
  PID/UID   COMMAND LINE                                       "             " 
 1612/1000  system_server                                  153760            14 
 
 
最健谈的system log: 
Chattiest UIDs in system log buffer:                         Size   +/-  Pruned 
UID   PACKAGE                                               BYTES           NUM 
1000  system                                               180236  -20%    8572 
  PID/UID   COMMAND LINE                                       "             " 
 1612/1000  system_server                                   69620          8238 
 2972/1000  com.coloros.persist.system                      68819           324 
 
 
最健谈的crash log: 
Chattiest UIDs in crash log buffer:                          Size 
UID   PACKAGE                                               BYTES 
0     root                                                    165 
 
 
最健谈的performance log: 
Chattiest UIDs in performance log buffer:                    Size 
UID   PACKAGE                                               BYTES 
1000  system                                                 2909 
  PID/UID   COMMAND LINE                                       " 
 1612/1000  system_server                                     556 
 
 
最健谈的PID: 
Chattiest PIDs:                                              Size        Pruned 
  PID/UID   COMMAND LINE                                    BYTES           NUM 
 2904/1001  com.android.phone                              270946          5604 
 1612/1000  system_server                                  240357         10661 
 
 
最健谈的TID: 
Chattiest TIDs:                                              Size        Pruned 
  TID/UID   COMM                                            BYTES           NUM 
 2904/1001  com.android.phone                              217685          4117 
 1765/1000  android.bg                                      78212           147 
 
 
最健谈的events log中的TAG: 
Chattiest events log buffer TAGs:                            Size         Prune 
    TAG/UID   TAGNAME                                       BYTES           NUM 
   1003       auditd                                        89160           390 
  30047/1000  am_pss                                        73004 
 
 
最健谈的TAG: 
Chattiest TAGs:                                              Size 
  TID/PID/UID   LOG_TAG NAME                                BYTES 
     2904/1001  SST                                        121294 
                auditd                                      89160

四、补充

1. logcat 有时候要和grep配合使用,而后者是区分大小写的,grep -i 就不再区分大小写了。


本文参考链接:https://www.cnblogs.com/hellokitty2/p/10276971.html