Re: [Quickfix-developers] QuickFIX 1.12.2 is 1 second slower than 1.11.1 on Logon turn-around and I do not know why

[iglen <ig...@ho...>]

Hi,=20

I seem to found at least partial possible explanation. One of the =
crucial
differences of two versions is that new version miss at least one beat =
of
blocked call because it first put connection object in the list of =
pending
connection (m_pendingConnections) which promoted to the connected =
connection
(m_connections) list only after first SocketMonitor::block() call.=20

Moreover when I have replace code in the SocketInitiator::doConnect()

From:
    setPending( s );

    m_pendingConnections[ result ]=20
          =3D new SocketConnection( *this, s, result,
&m_connector.getMonitor() );

To=20
    setConnected(s);

    m_connections[ result ]=20
          =3D new SocketConnection( *this, s, result,
&m_connector.getMonitor() );

It started to behave as old version at least as far as timing of Logon
turn-around is concerned.

It would be very interesting to learn the reason behind of pending
connections.

Thank you.

Len.

________________________________________
From: Leonid Gamburg [mailto:ig...@ho...]=20
Sent: Thursday, August 24, 2006 10:04 AM
To: qui...@li...
Subject: QuickFIX 1.12.2 is 1 second slower than 1.11.1 on Logon =
turn-around
and I do not know why

Hi,
=A0
I am trying to switch from=A0QuickFIX version 1.11.1=A0to QuickFIX =
version
1.12.2 because that version fixed bug when session could not timeout =
even if
remote engine never send messages in right order. When I switch to new
version I found that our Application every other connection timeout. =
After
debugging I have found that we impose on ourselves application's 2 =
second
timeout and disconnect immediately if no Logon message from remote party
been delivered to us. And new version of QuicFIX sometimes take bit less
than 2 seconds and sometimes more. When I have return previous engine =
back
it turn-around time (more on my definition of this term later) was =
around 1
second. I did a little bit more debugging but was not able to pinpoint =
the
reason for that discrepancy, but I am publishing information if other
developers have more clues.
=A0
=A0
The turn-around time for logon I would define as a=A0time it took to =
(and I
have modified QuickFIX a bit to be able to do it on demand) from enable
session and call Initiator::connect() and when the remote site send
FIX::Application::onLogon() propagated back to=A0our application code. =
The
mater here is bit complicated due to asynchronous nature of Logon() =
message
generation. Although enabling session and socket connection happens on =
the
invoking clinet thread Logon message generation sending happens on the
different thread.=20
=A0
On that different=A0thread (different from an Application's main thread) =
there
is a SocketMonitor::block() method which is being=A0invoked in the loop. =
If
there no activity on the sockets it will be blocked for for
SocketMonitor::getTimeval() microseconds which in both version returns =
the
same value equal to 1 second. After "select" invocation =
strategy.onTimeout()
is being called which eventually call Session::generateLogon() etc. The
bazaar part is that although SocketMonitor::block() methods (and other
SocketMonitor methods)=A0are very similar that select() call takes =
exactly 1
second on the 1.12.2 version and almost always 0.6 seconds on the =
1.11.1.
=A0
Although I do not know why this happens (may be there some sockets in =
the
1.11.1 version signal prior to 1 second timeout) that explains 0.4 =
seconds
difference. Where is other 0.6 second difference I do not know.
=A0
I was able to shorten Logon turn-around time significantly when I call
onTimeout() directly (and consequently generateLogon())=A0on the =
application's
main thread and so far it works great, but I am afraid that this may =
cause
some nasty concurrency problem. It seems to me that asynchronous Logon() =
in
the unmodified QuickFIX makes full sense because it seems to be done =
only
once per day/week. Because I have modified QuickFIX to =
create/logon/logout
session on demand to me it rather waste of time
=A0
Thank you
=A0
Len.
________________________________________
Search from any Web page with powerful protection. Get the FREE Windows =
Live
Toolbar Today! Try it now!