On Dec 4, 2015, at 1:16 AM, Peter <j...@zeus.net.au> wrote:
Since ObjectInputStream is a big hotspot, for testing purposes, I merged these
changes into my local version of River, my validating ObjectInputStream
outperforms the standard java ois
Then TaskManager, used by the test became a problem, with tasks in contention
up to 30% of the time.
Next I replaced TaskManager with an ExecutorService (River 3, only uses
TaskManager in tests now, it's no longer used by release code), but there was
still contention although not quite as bad.
Then I notice that tasks in the test call Thread.yield(), which tends to
thrash, so I replaced it with a short sleep of 100ms.
Now monitor state was a maximum of 5%, much better.
After these changes, the hotspot consuming 27% cpu was JERI's
ConnectionManager.connect, followed by Class.getDeclaredMethod at 15.5%,
Socket.accept 14.4% and Class.newInstance at 10.8%.
First - performance optimization: Unless you’re testing with real-life
workloads, in real-ife-like network environments, you’re wasting your time. In
the real world, clients discover services pretty rarely, and real-world
architects always make sure that communications time is small compared to
processing time. In the real world, remote call latency is controlled by
network bandwidth and the speed of light. Running in the integration test
environment, you’re seeing processor loads, not network loads. There isn’t any
need for this kind of micro-optimization. All you’re doing is delaying
shipping, no matter how wonderful you keep telling us it is.
My validating ois, originating from apache harmony, was modified to use
explicit constructors during deserialization. This addressed finalizer
attacks, final field immutability and input stream validation and the ois
itself places a limit on downloaded bytes by controlling array creation and
expecting a stream reset every so often, if it doesn't receive one, it throws
an exception The reset ensures the receiver will regain control of the stream
before any DOS can occur, even for long running connections that transfer a lot
of data. There is no support for circular links in object graphs at this stage.
The deserialization constructor accepts a parameter that's caller sensitive, so
each class in an object's inheritance hierarchy has it's own get field
namespace.
A child class can validate it's parent class invariants by creating a
superclass only instance, calling its constructor and passing the caller
sensitive parameter (it cannot create this itself, it's created by the ois),
once the class has validated all invariants including the superclasses , the
client class knows it's safe to proceed with construction, otherwise it throws
an exception, an instance has not been created and deserialization is
terminated there.
Validation is performed inside static methods, prior to an object instance
being created.
The openjdk team have adopted static method validation, but not the
constructor. Unfortunately, that alone, wouldn't provide the level of security
required for an internet visible service or registrar.
The constructor and validation are very simple to implement.
This would allow an internet based registrar to safely download only the
bootstrap proxy to clients, so the client can authenticate it, before
downloading Entry's for local filtering or ServiceUI, followed by the smart
proxy. This would be performed by proxy preparation. So clients using SDM
wouldn't require modification, with changes being backward compatible.
This would provide both security and delayed unmarshalling along with a
significant increase in performance, as clients only ever download what they
need and permit.
The validating ois was designed for bootstrap proxy's, the lookup service and
unicast discovery, but can be also implemented by services as well, as I have
done. A new constraint determines whether validating, or standard
serialization is used.
Since we can now take advantage of interface default methods, we have an
opportunity to alter the lookup service interface, should we wish to leave
existing methods as they are and implement delayed unmarshalling and
authenticate prior to unmarshalling smart proxy’s
Second - River on the Internet: We’ve talked about this as a community. River
on the Internet is your pet, not the community’s interest. Please stop trying
to make River on the Internet happen. It’s not going to happen.
If you want to indulge your obsession with making River safe for untrusted
code, call it something else and go do it on Github, or go to the Incubator and
build a new community. This community has talked about it and said it wasn’t
interested.
Third - You’ve been messing around with “qa-refactor” for what, 4 years now?
You keep sending out long emails telling us how great your local copy of River
is, and how great ‘qa-refactor’ is. But so far, it’s an exercise in
self-indulgence. You complain endlessly about us old Jini types blocking
progress, but you refuse to let your work be finished. It isn’t real until it
ships and someone uses it. If you want it to be real, you need to quit
screwing around with it, and ship something.
Recently, you posted:
If I had time, id do the following, I may be able to assist with some tasks:
1. Move trunk to trunk-old.
2. Copy Dennis' branch of qa-refactor-rename to trunk.
3. Copy new classes in RIVER-413 from trunk-old, and change all
instances of InetAddress.getLocalHost() to point to
LocalHostLookup.getLocalHost().
4. Go through all resolved issues in JIRA and mark as resolved
(you'll need my help).
5. Generate the release notes (summary of all resolved JIRA issues).
6. Add the generated release notes to the release documentation.
7. Check that River version has been updated to 3.0 (I think this has
been done, but check again anyway). Don't confuse the river
version with Jini standards versions on documents.
8. Run the tests one last time, change the qa tests on Hudson to
point to trunk.
9. Build the release artifacts.
10. Sign the release artifacts.
11. Post the release artifacts for voting.
12. Vote on release artifacts.
13. Release River 3.0.
That seemed like a reasonable suggestion. Why not follow your own plan?
Sorry to be harsh, but I think it’s time somebody said it.
Regards,
Greg Trasuk
.
Regards,
Peter.
Sent from my Samsung device.
Include original message
---- Original message ----
From: Bryan Thompson <br...@systap.com>
Sent: 03/12/2015 11:48:12 am
To: <dev@river.apache.org> <dev@river.apache.org>
Subject: Re: Trunk merge and thread pools
Great!
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On Wed, Dec 2, 2015 at 7:26 PM, Peter <j...@zeus.net.au> wrote:
Just tried wrapping an Executors.newCachedThreadPool with a thread factory
that creates threads as per the original
org.apache.river.thread.NewThreadAction.
Performance is much improved, the hotspot is gone.
There are regression tests with sun bug Id's, which cause oome. I thought
this might
prevent the executor from running, but to my surprise both tests pass.
These tests failed when I didn't pool threads and just let them be gc'd.
These tests created over 11000 threads with waiting tasks. In practise I
wouldn't expect that to happen as an IOException should be thrown. However
there are sun bug id's 6313626 and 6304782 for these regression tests, if
anyone has a record of these bugs or any information they can share, it
would be much appreciated.
It's worth noting that the jvm memory options should be tuned properly to
avoid oome in any case.
Lesson here is, creating threads and gc'ing them is much faster than
thread pooling if your thread pool is not well optimised..
It's worth noting that ObjectInputStream is now the hotspot for the test,
the tested code's hotspots are DatagramSocket and SocketInputStream.
ClassLoading is thread confined, there's a lot of class loading going on,
but because it is uncontended, it only consumes 0.2% cpu, about the same as
our security architecture overhead (non encrypted).
Regards,
Peter.
Sent from my Samsung device.
Include original message
---- Original message ----
From: Bryan Thompson <br...@systap.com>
Sent: 02/12/2015 11:25:03 pm
To: <dev@river.apache.org> <dev@river.apacheorg>
Subject: Re: Trunk merge and thread pools
Ah. I did not realize that we were discussing a river specific ThreadPool
vs a Java Concurrency classes ThreadPoolExecutor. I assume that it would
be difficult to just substitute in one of the standard executors?
Bryan
On Wed, Dec 2, 2015 at 8:18 AM, Peter <j...@zeus.net.au> wrote:
> First it's worth considering we have a very suboptimal threadpool. There
> are qa and jtreg tests that limit our ability to do much with ThreadPool.
>
> There are only two instances of ThreadPool, shared by various jeri
> endpoint implementations, and other components.
>
> The implementation is allowed to create numerous threads, only limited by
> available memory and oome. At least two tests cause it to create over
> 11000 threads.
>
> Also, it previously used a LinkedList queue, but now uses a
> BlockingQueue, however the queue still uses poll, not take.
>
> The limitation seems to be the concern by the original developers that
> there may be interdependencies between tasks. Most tasks are method
> invocations from incoming and outgoing remote calls.
>
> It probably warrants further investigation to see if there's a suitable
> replacement.
>
> Regards,
>
> Peter.
>
> Sent from my Samsung device.
> Include original message
> ---- Original message ----
> From: Bryan Thompson <br...@systap.com>
> Sent: 02/12/2015 09:46:13 am
> To: <dev@river.apache.org> <dev@river.apache.org>
> Subject: Re: Trunk merge and thread pools
>
> Peter,
>
> It might be worth taking this observation about the thread pool behavior to
> the java concurrency list. See what feedback you get. I would certainly
> be interested in what people there have to say about this.
>
> Bryan
>
>
>
