Shulou(Shulou.com)06/02 Report--

This article is to share with you about the memory management commands in linux, the editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

Check for memory leaks

1. Java memory imaging tool: jmap

Jmap-histo:live pid output specifies the memory histogram of pid survival

The first column, serial number, has no practical significance.

The second column, the number of object instances

The third column, the total memory occupied by the object instance, in bytes

Fourth column, object instance name

Last line, total number of instances and total memory footprint

2. Virtual machine statistics monitoring tool: jstat

Jstat-gcutil pid 10s records gc recycling information every 10s, such as:

S0 S1 E O M CCS YGC YGCT FGC FGCT GCT 0.00 80.28 38.44 4.19 96.53 93.94 13805 709.977 5 1.078 711.055 0.00 80.28 57.48 4.19 96.53 93.94 13805 709.977 5 1.078 711.055 0.00 80.28 71.95 4.19 96.53 93.94 13805 709.977 5 1.078 711.055 0.00 80.28 84.82 4.19 96.53 93.94 13805 709.977 5 1.078 711.055 77.88 0.00 4.89 4.19 96.53 93.94 13806 710.049 5 1.078 711.127 77.88 0.00 13.71 4.19 96.53 93.94 13806 710.049 5 1.078 711.127 77.88 0.00 26. 91 4.19 96.53 93.94 13806 710.049 5 1.078 711.127 0.00 83.91 2.54 4.19 96.53 93.94 13807 710.080 5 1.078 711.158

Utilization of S0 Survivor0 area

S1 Survivor1 area utilization

Utilization of E Eden area

O (Old) stands for old age usage

M meta space (MetaspaceSize) used as a percentage of current capacity

CCS compression usage ratio

P (Permanent) stands for permanent generation usage

YGC (Young GC) represents the number of Minor GC from application startup to sampling

YGCT represents Minor GC elapsed time from application startup to sampling (in seconds)

FGC (Full GC) represents the number of Full GC from application startup to sampling

FGCT (Full GC) represents Full GC elapsed time from application startup to sampling (in seconds)

GCT represents the total time (in seconds) from application startup to Minor & Full GC when sampling

These are the memory management commands in linux, and the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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