heapstats | JVMTI agent and JavaFX analyzer

by HeapStats C++ Version: Current License: GPL-2.0

X-Ray Key Features Code Snippets Community Discussions(2)Vulnerabilities Install Support

kandi X-RAY | heapstats Summary

heapstats is a C++ library typically used in User Interface, JavaFX applications. heapstats has no bugs, it has no vulnerabilities, it has a Strong Copyleft License and it has low support. You can download it from GitHub.

JVMTI agent and JavaFX analyzer to gather JVM runtime information for after-the-fact analysis.

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heapstats has a low active ecosystem.

It has 126 star(s) with 16 fork(s). There are 17 watchers for this library.

It had no major release in the last 6 months.

There are 1 open issues and 16 have been closed. On average issues are closed in 110 days. There are no pull requests.

It has a neutral sentiment in the developer community.

The latest version of heapstats is current.

Quality

heapstats has 0 bugs and 0 code smells.

Security

heapstats has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

heapstats code analysis shows 0 unresolved vulnerabilities.

There are 0 security hotspots that need review.

License

heapstats is licensed under the GPL-2.0 License. This license is Strong Copyleft.

Strong Copyleft licenses enforce sharing, and you can use them when creating open source projects.

Reuse

heapstats releases are not available. You will need to build from source code and install.

It has 10406 lines of code, 785 functions and 124 files.

It has medium code complexity. Code complexity directly impacts maintainability of the code.

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heapstats Key Features

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heapstats Examples and Code Snippets

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Community Discussions

Trending Discussions on heapstats

V8 Memory leak when using optional chaining in script

How to get Current and accurate Memory Usage of k8s Pod running Node JS application

QUESTION

V8 Memory leak when using optional chaining in script

Asked 2021-Dec-10 at 17:47

I've embedded V8 9.5 into my app (C++ HTTP server). When I started to use optional chaining in my JS scripts I've noticed abnormal rise in memory consumption under heavy load (CPU) leading to OOM. While there's some free CPU, memory usage is normal. I've displayed V8 HeapStats in grafana (this is only for 1 isolate, which I have 8 in my app)

Under heavy load there's a spike in peak_malloced_memory, while other stats are much less affected and seem normal. I've passed --expose-gc flag to V8 and called gc() at the end of my script. It completely solved the problem and peak_malloced_memory doesn't rise like that. Also, by repeatedly calling gc() I could free all extra memory consumed without it. --gc-global also works. But these approaches seem more like a workaround rather than a production-ready solution. --max-heap-size=64 and --max-old-space-size=64 had no effect - memory consumption still did greatly exceed 8(number of isolates in my app)*64Mb (>2Gb physical RAM).

I don't use any GC-related V8 API in my app.

My app creates v8::Isolate and v8::Context once and uses them to process HTTP requests.

Same behavior at v9.7.

Ubuntu xenial

Built V8 with these args.gn

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ANSWER

Answered 2021-Nov-29 at 17:46

(V8 developer here.)

Is it normal that peak_malloced_memory can exceed total_heap_size?

Malloced memory is unrelated to the heap, so yes, when the heap is tiny then malloced memory (which typically also isn't a lot) may well exceed it, maybe only briefly. Note that peak malloced memory (53 MiB in your screenshot) is not current malloced memory (24 KiB in your screenshot); it's the largest amount that was used at any point in the past, but has since been freed (and is hence not a leak, and won't cause an OOM over time).

Not being part of the heap, malloced memory isn't affected by --max-heap-size or --max-old-space-size, nor by manual gc() calls.

Why could this occur only when using JS's optional chaining?

That makes no sense, and I bet that something else is going on.

Are there any other, more correct solutions to this problem other than forcing full GC all the time?

I'm not sure what "this problem" is. A brief peak of malloced memory (which is freed again soon) should be fine. Your question title mentions a "leak", but I don't see any evidence of a leak. Your question also mentions OOM, but the graph doesn't show anything related (less than 10 MiB current memory consumption at the end of the plotted time window, with 2GB physical memory), so I'm not sure what to make of that.

Manually forcing GC runs is certainly not a good idea. The fact that it even affects (non-GC'ed!) malloced memory at all is surprising, but may have a perfectly mundane explanation. For example (and I'm wildly speculating here, since you haven't provided a repro case or other more specific data), it could be that the short-term peak is caused by an optimized compilation, and with the forced GC runs you're destroying so much type feedback that the optimized compilation never happens.

Happy to take a closer look if you provide more data, such as a repro case. If the only "problem" you see is that peak_malloced_memory is larger than the heap size, then the solution is simply not to worry about it.

Source https://stackoverflow.com/questions/70157768

QUESTION

How to get Current and accurate Memory Usage of k8s Pod running Node JS application

Asked 2021-Nov-14 at 01:12

I have a NodeJS application running on a k8s pod. The actual size of the pod is 2GB, but in environment variables, we set this value to 4GB --max-old-space-size=4096 (which will not be true in my case - for some tenants we do allocate 4GB but most pods have 2GB).

Now I tried 2 ways to detect the memory usage and the total memory and both are providing different stats.

I'm fetching memory usage from this system file: /sys/fs/cgroup/memory/memory.usage_in_bytes and total memory from this file : /sys/fs/cgroup/memory/memory.limit_in_bytes

limit_in_bytes is returning 2GB correctly, but the value of usage_in_bytes is fluctuating too much, It's around 1gb in few mins and spikes to 2GB in next minute even though nothing changed in that minute(no stress on the system).

Stats of a process

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ANSWER

Answered 2021-Nov-14 at 01:12

To get overall memory consumption of a process, look to (and trust) the operating system's facilities.

Node's v8.getHeapStatistics tell you about the managed (a.k.a. garbage-collected) heap where all the JavaScript objects live. But there can be quite a bit of other, non-garbage-collected memory in the process, for example Node buffers and certain strings, and various general infrastructure that isn't on the managed heap. In the average Chrome renderer process, the JavaScript heap tends to be around a third of total memory consumption, but with significant outliers in both directions; for Node apps it depends a lot on what your app is doing.

Setting V8's max heap size (which, again, is just the garbage-collected part of the process' overall memory usage) to a value larger than the amount of memory available to you doesn't make much sense: it invites avoidable crashes, because V8 won't spend as much time on garbage collection when it thinks there's lots of available memory left, but the OS/pod as a whole could already be facing an out-of-memory situation at that point. That's why I linked the other answer: you very likely want to set the max heap size to something a little less than available memory, to give the garbage collector the right hints about when to work harder to stay under the limit.

Source https://stackoverflow.com/questions/69956279

Community Discussions, Code Snippets contain sources that include Stack Exchange Network

Vulnerabilities

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You can download it from GitHub.

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