Consider the following scenario:
A data packet is sent out of a serial port and a return packet is expected a
short time later.
The application sending the packet needs to send another packet as soon as
the return packet has been received. It needs to wait for the return packet,
but time out if one is not received.
Whilst packets are being exchanged the application needs to be responsive.
To maximise throughput, should the packets be sent on a separate thread? How
would the application wait for the thread to complete (without blocking) in
order to send subsequent packets? Looping with DoEvents causes CPU % to
shoot up, and Sleep(x) introduces excessive delays between packets.
TIA
Charles
20  2011 
Charles,
Dependent on the method (an RS232 control, API-calls, ...) you use to
communicate with RS232, you might make use of an event or a callback
whenever return-data comes in.
Regards,
jan
"Charles Law" <bl***@nowhere. com> wrote in message
news:e6******** ********@TK2MSF TNGP12.phx.gbl. .. Consider the following scenario:
A data packet is sent out of a serial port and a return packet is expected
a short time later.
The application sending the packet needs to send another packet as soon as
the return packet has been received. It needs to wait for the return
packet, but time out if one is not received.
Whilst packets are being exchanged the application needs to be responsive.
To maximise throughput, should the packets be sent on a separate thread?
How would the application wait for the thread to complete (without blocking)
in order to send subsequent packets? Looping with DoEvents causes CPU % to
shoot up, and Sleep(x) introduces excessive delays between packets.
TIA
Charles
Hi Charles,
I do it by just let the subthread raise an public event and set a handler
for that in the program that starts the thread.
What do I mis?
Cor Consider the following scenario:
A data packet is sent out of a serial port and a return packet is expected
a short time later.
The application sending the packet needs to send another packet as soon as
the return packet has been received. It needs to wait for the return
packet, but time out if one is not received.
Whilst packets are being exchanged the application needs to be responsive.
To maximise throughput, should the packets be sent on a separate thread?
How would the application wait for the thread to complete (without blocking)
in order to send subsequent packets? Looping with DoEvents causes CPU % to
shoot up, and Sleep(x) introduces excessive delays between packets.
TIA
Charles
Hi Jan
I have an event that is raised when data is received, and I do my packet
detection there. This event is already on a separate thread, so once a
complete packet has been received I just set a flag to indicate the arrival.
My main send and receive thread needs to wait for this flag, but I don't
want to use excessive cpu time effectively polling the flag until it is set.
That is why I wondered about a wait on another thread, or something like
that.
Charles
"Jan" <ms****@tss.b e> wrote in message
news:%2******** ********@TK2MSF TNGP11.phx.gbl. .. Charles,
Dependent on the method (an RS232 control, API-calls, ...) you use to
communicate with RS232, you might make use of an event or a callback
whenever return-data comes in.
Regards,
jan
"Charles Law" <bl***@nowhere. com> wrote in message
news:e6******** ********@TK2MSF TNGP12.phx.gbl. .. Consider the following scenario:
A data packet is sent out of a serial port and a return packet is
expected a short time later.
The application sending the packet needs to send another packet as soon
as the return packet has been received. It needs to wait for the return
packet, but time out if one is not received.
Whilst packets are being exchanged the application needs to be
responsive.
To maximise throughput, should the packets be sent on a separate thread?
How would the application wait for the thread to complete (without blocking)
in order to send subsequent packets? Looping with DoEvents causes CPU % to
shoot up, and Sleep(x) introduces excessive delays between packets.
TIA
Charles
Hi Cor
The reason I haven't done this is because the main thread needs to wait for
the return packet before sending the next packet out.
At some point, it seems to me, there has to be a wait in order to keep the
packets transferring synchronously.
I had thought of doing it something like this:
Application thread
------------------
Do
Wait for send thread to terminate
Start send thread to send packet
Loop
Send thread
------------
Send packet
Wait for return packet to be received; timeout if none received.
Terminate thread
but I cannot work out how to do this without wasting time polling the send
thread and blocking the application thread.
Charles
"Cor" <no*@non.com> wrote in message
news:ex******** ******@TK2MSFTN GP12.phx.gbl... Hi Charles,
I do it by just let the subthread raise an public event and set a handler
for that in the program that starts the thread.
What do I mis?
Cor
Consider the following scenario:
A data packet is sent out of a serial port and a return packet is
expected a short time later.
The application sending the packet needs to send another packet as soon
as the return packet has been received. It needs to wait for the return
packet, but time out if one is not received.
Whilst packets are being exchanged the application needs to be
responsive.
To maximise throughput, should the packets be sent on a separate thread?
How would the application wait for the thread to complete (without blocking)
in order to send subsequent packets? Looping with DoEvents causes CPU % to
shoot up, and Sleep(x) introduces excessive delays between packets.
TIA
Charles
Hi Charles,
That is what I had in a program, but now it is just as beneath, I deleted a
lot and changed the Dutch a little bit to English
So it is just for the idea what I am doing, I hope I did not cut to much it
are more classes you know.
Cor
\\\
Application thread
Private WithEvents SendThread As New clsSendThread
Protected Sub threadReady() Handles SendThread.thre adReady
do some things,
Sendthread.main ()
End Sub
/// clsSendthread
Public Event threadReady()
main Sub
ThreadAThread = New System.Threadin g.Thread(Addres sOf ThreadA)
ThreadAThread.S tart()
end sub
Private Sub ThreadA()
Dim myfunction As New TheFunction()
doReady(myfunct ion.doyourthing s)
End Sub
Private Sub doReady(ByVal errors As String)
do some things
RaiseEvent threadKlaar()
End Sub
///
Charles,
In case the required processing is not too extensive, you might just do it
in that event, instead of only setting a flag.
Regards,
Jan
"Charles Law" <bl***@nowhere. com> wrote in message
news:u9******** ******@TK2MSFTN GP10.phx.gbl... Hi Jan
I have an event that is raised when data is received, and I do my packet
detection there. This event is already on a separate thread, so once a
complete packet has been received I just set a flag to indicate the
arrival. My main send and receive thread needs to wait for this flag, but I don't
want to use excessive cpu time effectively polling the flag until it is
set. That is why I wondered about a wait on another thread, or something like
that.
Charles
"Jan" <ms****@tss.b e> wrote in message
news:%2******** ********@TK2MSF TNGP11.phx.gbl. .. Charles,
Dependent on the method (an RS232 control, API-calls, ...) you use to
communicate with RS232, you might make use of an event or a callback
whenever return-data comes in.
Regards,
jan
"Charles Law" <bl***@nowhere. com> wrote in message
news:e6******** ********@TK2MSF TNGP12.phx.gbl. .. Consider the following scenario:
A data packet is sent out of a serial port and a return packet is expected a short time later.
The application sending the packet needs to send another packet as
soon as the return packet has been received. It needs to wait for the return
packet, but time out if one is not received.
Whilst packets are being exchanged the application needs to be responsive.
To maximise throughput, should the packets be sent on a separate
thread? How would the application wait for the thread to complete (without
blocking) in order to send subsequent packets? Looping with DoEvents causes CPU %
to shoot up, and Sleep(x) introduces excessive delays between packets.
TIA
Charles
Jan
The processing required is actually to send the next packet, and then wait
for a return packet. If I do this in the event I'm in danger of entering a
recursive spiral, as the event will be raised for the return packet,
whereupon I send out the next packet and wait for the return, and continue
to go deeper and deeper.
Charles
"Jan" <ms****@tss.b e> wrote in message
news:%2******** ********@tk2msf tngp13.phx.gbl. .. Charles,
In case the required processing is not too extensive, you might just do it
in that event, instead of only setting a flag.
Regards,
Jan
"Charles Law" <bl***@nowhere. com> wrote in message
news:u9******** ******@TK2MSFTN GP10.phx.gbl... Hi Jan
I have an event that is raised when data is received, and I do my packet
detection there. This event is already on a separate thread, so once a
complete packet has been received I just set a flag to indicate the
arrival. My main send and receive thread needs to wait for this flag, but I don't
want to use excessive cpu time effectively polling the flag until it is
set. That is why I wondered about a wait on another thread, or something like
that.
Charles
"Jan" <ms****@tss.b e> wrote in message
news:%2******** ********@TK2MSF TNGP11.phx.gbl. .. Charles,
Dependent on the method (an RS232 control, API-calls, ...) you use to
communicate with RS232, you might make use of an event or a callback
whenever return-data comes in.
Regards,
jan
"Charles Law" <bl***@nowhere. com> wrote in message
news:e6******** ********@TK2MSF TNGP12.phx.gbl. ..
> Consider the following scenario:
>
> A data packet is sent out of a serial port and a return packet is
expected a
> short time later.
>
> The application sending the packet needs to send another packet as soon as > the return packet has been received. It needs to wait for the return
packet,
> but time out if one is not received.
>
> Whilst packets are being exchanged the application needs to be
responsive. >
> To maximise throughput, should the packets be sent on a separate
thread? How
> would the application wait for the thread to complete (without blocking) in
> order to send subsequent packets? Looping with DoEvents causes CPU % to > shoot up, and Sleep(x) introduces excessive delays between packets.
>
> TIA
>
> Charles
>
>
Hi Cor
I'm not sure I understand what happens here, but it looks like I would need
a wait in there somewhere whilst the return packet comes in. Otherwise, the
process would just run through and terminate and the next packet could get
sent out before the previous return packet had been received. Have I
misunderstood?
Charles
"Cor" <no*@non.com> wrote in message
news:et******** ******@TK2MSFTN GP10.phx.gbl... Hi Charles,
That is what I had in a program, but now it is just as beneath, I deleted
a lot and changed the Dutch a little bit to English
So it is just for the idea what I am doing, I hope I did not cut to much
it are more classes you know.
Cor
\\\
Application thread
Private WithEvents SendThread As New clsSendThread
Protected Sub threadReady() Handles SendThread.thre adReady
do some things,
Sendthread.main ()
End Sub
/// clsSendthread
Public Event threadReady()
main Sub
ThreadAThread = New System.Threadin g.Thread(Addres sOf ThreadA)
ThreadAThread.S tart()
end sub
Private Sub ThreadA()
Dim myfunction As New TheFunction()
doReady(myfunct ion.doyourthing s)
End Sub
Private Sub doReady(ByVal errors As String)
do some things
RaiseEvent threadKlaar()
End Sub
///
Hi Charles,
It are three classes.
The main class
A starter stopper class
A class that does the things in a thread (You do not see that , only the
declaration of it)
for me it looks very much as your problem.
Have a look for it, I have also something with a timer, but that is not what
you want I think.
Cor
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