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<== Date ==> <== Thread ==>

Subject: RE: Bandwidth limits in asyn
From: Mark Rivers <rivers@cars.uchicago.edu>
To: 'Iain Marcuson' <Iain.Marcuson@sydorinstruments.com>, "tech-talk@aps.anl.gov >> EPICS Tech Talk" <tech-talk@aps.anl.gov>
Date: Fri, 21 Apr 2017 17:46:18 +0000
If the diagnostics on each end don't solve the problem you may want to look at the network traffic with Wireshark.

Mark


-----Original Message-----
From: Iain Marcuson [mailto:Iain.Marcuson@sydorinstruments.com] 
Sent: Friday, April 21, 2017 8:50 AM
To: Mark Rivers; tech-talk@aps.anl.gov >> EPICS Tech Talk
Subject: RE: Bandwidth limits in asyn

I wrote a C program to read the data, and it also fails at about the same point.  The camera is a custom one, so I can put any diagnostics on it I want.

Iain.

> -----Original Message-----
> From: Mark Rivers [mailto:rivers@cars.uchicago.edu]
> Sent: Thursday, April 20, 2017 5:17 PM
> To: Iain Marcuson <Iain.Marcuson@sydorinstruments.com>
> Subject: RE: Bandwidth limits in asyn
> 
> It does not sound to me like the error you are getting has anything to do with
> the fact that you are using asyn or EPICS.  Have you tried a simple C test
> program to read the data from the device?  It seems like a low-level
> communication problem.  What is the camera device on the other end of the
> wire?  Do you have access to any diagnostics on that end?
> 
> Mark
> 
> 
> -----Original Message-----
> From: Iain Marcuson [mailto:Iain.Marcuson@sydorinstruments.com]
> Sent: Thursday, April 20, 2017 3:50 PM
> To: Mark Rivers
> Subject: RE: Bandwidth limits in asyn
> 
> I am using recv() on a socket opened in the constructor.  Recv() returns a -1
> and perror() says "Bad address".  In  the mockup server I made using Python,
> it reported "socket.error: [Errno 104] Connection reset by peer".
> 
> Iain.
> 
> > -----Original Message-----
> > From: Mark Rivers [mailto:rivers@cars.uchicago.edu]
> > Sent: Thursday, April 20, 2017 4:47 PM
> > To: Iain Marcuson <Iain.Marcuson@sydorinstruments.com>; tech-
> > talk@aps.anl.gov >> EPICS Tech Talk <tech-talk@aps.anl.gov>
> > Subject: RE: Bandwidth limits in asyn
> >
> > What function does your readInt16Array function call to do the network
> > transfer?  Are you using the native socket calls, i.e. recv() or recvfrom()?
> >
> > Are you using the EPICS osiSock.h to make your driver portable to
> > different OS?
> >
> > When you say "the connection breaks" what exactly do you mean?  Is
> > recv() or recvfrom() returning 0 or a negative number?
> >
> > Mark
> >
> >
> > -----Original Message-----
> > From: Iain Marcuson [mailto:Iain.Marcuson@sydorinstruments.com]
> > Sent: Thursday, April 20, 2017 3:36 PM
> > To: Mark Rivers; tech-talk@aps.anl.gov >> EPICS Tech Talk
> > Subject: RE: Bandwidth limits in asyn
> >
> > I am calling my own asynPortDriver function with the readInt16Array
> > method.  This is 1 Gbit Ethernet.  On my most recent run, it took
> > 0.854 seconds to receive 19214960 bytes.
> >
> >
> > > -----Original Message-----
> > > From: Mark Rivers [mailto:rivers@cars.uchicago.edu]
> > > Sent: Thursday, April 20, 2017 4:06 PM
> > > To: Iain Marcuson <Iain.Marcuson@sydorinstruments.com>; tech-
> > > talk@aps.anl.gov >> EPICS Tech Talk <tech-talk@aps.anl.gov>
> > > Subject: RE: Bandwidth limits in asyn
> > >
> > > How are you reading the data, i.e. are you calling the drvAsynIPPort
> > > driver from your driver?
> > >
> > > If so, how have you called drvAsynIPPortConfigure?  What value are
> > > you specifying for the timeout?
> > >
> > > Is this 1 Gbit Ethernet?
> > >
> > > What is the time between when you start the transfer and it breaks
> > > after
> > > 17640000 bytes?
> > >
> > > Mark
> > >
> > >
> > > -----Original Message-----
> > > From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-
> > > bounces@aps.anl.gov] On Behalf Of Iain Marcuson
> > > Sent: Thursday, April 20, 2017 2:28 PM
> > > To: tech-talk@aps.anl.gov >> EPICS Tech Talk
> > > Subject: Bandwidth limits in asyn
> > >
> > > I've been writing an asyn driver to receive data from a camera, but
> > > I seem to be hitting some sort of limit.  The total size to transmit
> > > is
> > > 35280000 bytes, but the connection breaks at around 17640000 bytes.
> > > In a mockup test, I was able to transfer all the data by sending 16k
> > > with a pause of 0.5 seconds between each packet.  The receiving
> > > routine just buffers all the incoming data until it reads the
> > > predetermined amount.  Is there something else I need to be doing to
> > > get
> > all the data?
> > >
> > > Thank you,
> > >
> > > Iain.

References:
Bandwidth limits in asyn Iain Marcuson
RE: Bandwidth limits in asyn Mark Rivers
RE: Bandwidth limits in asyn Iain Marcuson
RE: Bandwidth limits in asyn Mark Rivers
RE: Bandwidth limits in asyn Iain Marcuson

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