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https://issues.apache.org/jira/browse/SSHD-742?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15981406#comment-15981406
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Goldstein Lyor commented on SSHD-742:
-------------------------------------
Before we can answer this rather general issue there are several key issues
that need to be clarified:
{quote}
Is there any way I can improve the performance?
{quote}
Any specific part of SSHD ? The _Java Flight Recorder_ report you mention seems
to be related to the shell, but SSH is much more than that - e.g., command
channel, SFTP, SCP. Is there a particular area of performance you are
interested in ?
{quote}
the throughput was particularly low - 2400 requests per second
{quote}
Please be specific - what are these "requests" you measure ? What cipher are
you using ? Are you using compression ?
{quote}
The documentation is kinda sparse
{quote}
It is actually quite detailed - perhaps is lacks emphasis on what interests you
- if so, please specify what is missing so we can complete it. In any case,
there are many (many, many.,..) configuration parameters that can be used to
tweak the performance, but unless a specific performance metric and/or target
use-case is indicated it is difficult to advise on which parameters to
concentrate and how to tweak them.
{quote}
I was quite disappointed because the throughput was particularly low
{quote}
"Low" compared to what benchmark ? What exact environment were you using - O/S,
Heap memory size, GC configuration, concurrent NIO threads, which I/O factory ?
etc., etc..
I have reviewed the code and there are many issues that adversely affect
performance in the way the server/client are set-up - here are jst a few
{code:java|title=Server}
ExecutorService threadPool = Executors.newSingleThreadExecutor(); // used to
run commands but only one at a time
server.setNioWorkers(1); // severly limits throughput
// Exit callback not propagated to the MessageReceiver and thus channel is not
closed as it should be - clearly documented as a requirement: "Once the command
is done, it should call the ExitCallback#onExit method to indicate that it has
finished"
@Override
public void start(Environment environment) {
threadPool.submit(new MessageReceiver(input, output, MESSAGE_SEPARATOR,
payload));
}
{code}
{code:java|title=Client}
// Should be inside a try-with-resource block
ClientChannel channel = session.createChannel(Channel.CHANNEL_SUBSYSTEM,
"messaging");
channel.open(); // not the proper way to open a channel
{code}
> Are there any ways to improve performance?
> ------------------------------------------
>
> Key: SSHD-742
> URL: https://issues.apache.org/jira/browse/SSHD-742
> Project: MINA SSHD
> Issue Type: Question
> Affects Versions: 1.4.0
> Environment: https://github.com/maseev/sshd-echo
> Reporter: Miron Aseev
> Priority: Minor
>
> I created a simple client-server application (see the environment section)
> that uses MINA SSHD library, just to test the performance. I was quite
> disappointed because the throughput was particularly low - 2400 requests per
> second on average on localhost.
> According to Java Flight Recorder, the application spends most of its time in
> ChannelPipedInputStream/ChannelPipedOutputStream on different monitor objects.
> Is there any way I can improve the performance? The documentation is kinda
> sparse and doesn't mention any tuning suggestions. Maybe I can avoid using
> these piped streams somehow or set some parameters related to the transport
> layer?
> All suggestions are greatly appreciated.
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