From asaf.mesika at gmail.com  Wed Aug 17 07:05:42 2022
From: asaf.mesika at gmail.com (Asaf Mesika)
Date: Wed, 17 Aug 2022 10:05:42 +0300
Subject: OperatingSystemMXBean and network usage and limit information
Message-ID: <CA+r7Yv=sS7+MxFgxm-LijXfeDjrYjo7kRALQUxo-9n_Akh=wwg@mail.gmail.com>

Hi,

I've searched through the various mailing lists, but couldn't find a
suitable one so I'm posting it here.

I would like to have the ability to know from an application the current
network usage and limit (relative to host or cgroup).

I have seen the class  OperatingSystemMXBean that is provided by the JDK. I
was wondering if the idea of adding that information to this bean has been
considered in the past.

Currently, the best option I found, which is operating system-specific
code, is to use the /sys/class/net/ files.

Thanks,

Asaf
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From sgehwolf at redhat.com  Wed Aug 17 08:59:14 2022
From: sgehwolf at redhat.com (Severin Gehwolf)
Date: Wed, 17 Aug 2022 10:59:14 +0200
Subject: OperatingSystemMXBean and network usage and limit information
In-Reply-To: <CA+r7Yv=sS7+MxFgxm-LijXfeDjrYjo7kRALQUxo-9n_Akh=wwg@mail.gmail.com>
References: <CA+r7Yv=sS7+MxFgxm-LijXfeDjrYjo7kRALQUxo-9n_Akh=wwg@mail.gmail.com>
Message-ID: <b1a96ed4ebec9b0de888b18741e86669e0e41f48.camel@redhat.com>

Hi,

On Wed, 2022-08-17 at 10:05 +0300, Asaf Mesika wrote:
> Hi,
> 
> I've searched through the various mailing lists, but couldn't find a
> suitable?one so I'm posting it here.
> 
> I would like to have the ability to know from an application the
> current network usage and limit (relative to host or cgroup).
> 
> I have seen the class??OperatingSystemMXBean?that is provided by the
> JDK. I was wondering if the idea of adding that information?to this
> bean has been considered in the past.
> 
> Currently, the best option I found, which is operating system-
> specific code, is to use the?/sys/class/net/?files.

One challenge for this would be to do this in a version agnostic way.
Another is that nothing is using this info at present and we'd have to
have a compelling use-case where adding such an API would be useful.?

AFAIK, net_cls which would allow something like that in v1, does not
exist for v2.

With all that said, I don't think there are any plans to do this.

Thanks,
Severin


From hohensee at amazon.com  Wed Aug 17 18:40:03 2022
From: hohensee at amazon.com (Hohensee, Paul)
Date: Wed, 17 Aug 2022 18:40:03 +0000
Subject: OperatingSystemMXBean and network usage and limit information
Message-ID: <2730DAF1-DA41-4E35-B3E7-A541DA336211@amazon.com>

This is a serviceability-dev issue, redirected.

Thanks,
Paul

?-----Original Message-----
From: discuss <discuss-retn at openjdk.org> on behalf of Severin Gehwolf <sgehwolf at redhat.com>
Date: Wednesday, August 17, 2022 at 2:00 AM
To: "discuss at openjdk.org" <discuss at openjdk.org>
Subject: RE: OperatingSystemMXBean and network usage and limit information

Hi,

On Wed, 2022-08-17 at 10:05 +0300, Asaf Mesika wrote:
> Hi,
>
> I've searched through the various mailing lists, but couldn't find a
> suitable one so I'm posting it here.
>
> I would like to have the ability to know from an application the
> current network usage and limit (relative to host or cgroup).
>
> I have seen the class  OperatingSystemMXBean that is provided by the
> JDK. I was wondering if the idea of adding that information to this
> bean has been considered in the past.
>
> Currently, the best option I found, which is operating system-
> specific code, is to use the /sys/class/net/ files.

One challenge for this would be to do this in a version agnostic way.
Another is that nothing is using this info at present and we'd have to
have a compelling use-case where adding such an API would be useful.

AFAIK, net_cls which would allow something like that in v1, does not
exist for v2.

With all that said, I don't think there are any plans to do this.

Thanks,
Severin



From maxim.kartashev at jetbrains.com  Tue Aug 30 06:50:22 2022
From: maxim.kartashev at jetbrains.com (Maxim Kartashev)
Date: Tue, 30 Aug 2022 09:50:22 +0300
Subject: Any interest in WatchService based on MacOS FSEvents?
Message-ID: <CAG0Tb0iSUqxHfT22b4x3Vp71rwzG94yNyZLzo6gMMJEZEx+e-g@mail.gmail.com>

WatchService on MacOS is still implemented by the generic
PollingWatchService, which continuously re-scans the directory consuming
CPU, introduces large latencies to the generated WatchEvent's, and misses
changes that occur faster than the re-scan interval. At the same time,
there are two technologies available on the platform to receive the
necessary information from the OS similar to what is available on Windows
and Linux: Kernel Queues and File System Events, the latter being more
suitable for implementing the WatchServie functionality.

There are several stand-alone implementations out there that utilize one or
the other (or even both), which suggests that demand exists for
WatchService on MacOS to be more responsive and less resource-hungry.

If the community is interested in getting this functionality in OpenJDK
proper, I'd be happy to contribute code that was developed, tested, and
used at JetBrains for around half a year. It is based on FSEvents, supports
the FILE_TREE modifier (recursive directory watch), and does not do any
excessive I/O except the necessary minimum.

References
* WatchService interface
  -
https://docs.oracle.com/en/java/javase/18/docs/api/java.base/java/nio/file/WatchService.html
* PollingWatchService source code
  -
https://github.com/openjdk/jdk/blob/master/src/java.base/share/classes/sun/nio/fs/PollingWatchService.java
* File System Events
  -
https://developer.apple.com/documentation/coreservices/file_system_events?language=objc
* Kernel Queues
  -
https://developer.apple.com/library/archive/documentation/Darwin/Conceptual/FSEvents_ProgGuide/KernelQueues/KernelQueues.html
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From marius at volkhart.com  Tue Aug 30 23:21:41 2022
From: marius at volkhart.com (Marius Volkhart)
Date: Tue, 30 Aug 2022 19:21:41 -0400
Subject: Any interest in WatchService based on MacOS FSEvents?
In-Reply-To: <CAG0Tb0iSUqxHfT22b4x3Vp71rwzG94yNyZLzo6gMMJEZEx+e-g@mail.gmail.com>
References: <CAG0Tb0iSUqxHfT22b4x3Vp71rwzG94yNyZLzo6gMMJEZEx+e-g@mail.gmail.com>
Message-ID: <9864649E-054C-4160-9049-3996B7F69C25@volkhart.com>

Hi Maxim,

I think this would be great, and would be very pleased to see it in the JDK.

Cheers,
Marius 

> On Aug 30, 2022, at 02:52, Maxim Kartashev <maxim.kartashev at jetbrains.com> wrote:
> 
> ?
> WatchService on MacOS is still implemented by the generic PollingWatchService, which continuously re-scans the directory consuming CPU, introduces large latencies to the generated WatchEvent's, and misses changes that occur faster than the re-scan interval. At the same time, there are two technologies available on the platform to receive the necessary information from the OS similar to what is available on Windows and Linux: Kernel Queues and File System Events, the latter being more suitable for implementing the WatchServie functionality.
> 
> There are several stand-alone implementations out there that utilize one or the other (or even both), which suggests that demand exists for WatchService on MacOS to be more responsive and less resource-hungry. 
> 
> If the community is interested in getting this functionality in OpenJDK proper, I'd be happy to contribute code that was developed, tested, and used at JetBrains for around half a year. It is based on FSEvents, supports the FILE_TREE modifier (recursive directory watch), and does not do any excessive I/O except the necessary minimum.
> 
> References
> * WatchService interface 
>   - https://docs.oracle.com/en/java/javase/18/docs/api/java.base/java/nio/file/WatchService.html
> * PollingWatchService source code 
>   - https://github.com/openjdk/jdk/blob/master/src/java.base/share/classes/sun/nio/fs/PollingWatchService.java
> * File System Events 
>   - https://developer.apple.com/documentation/coreservices/file_system_events?language=objc
> * Kernel Queues 
>   - https://developer.apple.com/library/archive/documentation/Darwin/Conceptual/FSEvents_ProgGuide/KernelQueues/KernelQueues.html
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