RE: Bandwidth limits in asyn

[Mark Rivers <rivers@cars.uchicago.edu>]

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.