Why is the number of threads in a java process different from the actual size of non-heap memory?

Question

The sentences may be strange due to my lack of English knowledge Thanks to everyone who reads the question.

Hello?

I am running a java process on Centos7 and monitoring it with jconsole, but the number of threads currently created is different in non-heap memory size.

I know that one thread occupies 1mb by default, but even if 100thread is created, the size of non-heap memory is not 100mb. Why?

Thread stacks are not the only thing that lives in non-heap memory. So the values being "different" is not suprising. Are they higher or lower than what you expected? — Joachim Sauer, Mar 05 '22 at 13:42
Thank you for answer. There are 200 threads, but the memory is about 100mb. Less memory usage than expected. — WooSub Shin, Mar 05 '22 at 13:48
So, can't the thread stack memory be checked as non-heap memory? Do I need to infer thread stack memory by thread number? — WooSub Shin, Mar 05 '22 at 13:54
Sorry for frequently asking rudimentary questions. Thank you so much for your kind replies. So, when do you need thread stack memory? — WooSub Shin, Mar 05 '22 at 14:10
Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. — Community, Mar 05 '22 at 16:04

score 0 · Accepted Answer · answered Mar 05 '22 at 19:55

0

Non-Heap memory, as shown by jconsole, includes Metaspace, Compressed Class Space and Code Cache. In other words, it counts memory used by loaded classes and compiled methods. It has nothing to do with threads and stacks.

answered Mar 05 '22 at 19:55

apangin

92,924
10
193
247

I thought until now that non-heap memory contains the thread stack. But it doesn't. Thanks for your reply. – WooSub Shin Mar 06 '22 at 06:24

Why is the number of threads in a java process different from the actual size of non-heap memory?

1 Answers1