RE: StreamDevice slowdown

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

To be sure that the problem is streamDevice rather than something else in EPICS, you could use the asynRecord to do the tests.  Put the OFMT=ASCII, IFMT=Binary, and make the IMAX be large enough to hold your waveform when you boot the IOC.
 
Mark
 

________________________________

From: Eric Norum [mailto:wenorum@lbl.gov]
Sent: Sun 9/26/2010 5:25 PM
To: Mark Rivers
Cc: tech-talk@aps.anl.gov; Dirk Zimoch
Subject: Re: StreamDevice slowdown



To check the raw transfer speed I did:
         telnet  -c  192.168.1.159 73 >/dev/null
and typed in the 'Waveform?\n" command. 

The times per megasample for 16 megasamples in this case:
10.25
10.24
10.24
10.25
10.24
10.25
10.24
10.25
10.24
10.25
10.24
10.25
10.24
10.25
10.24
10.24

So I'm pretty sure that the slowdown is in the StreamDevice processing somewhere.

By way of comparison, here are the 16 'seconds per megasample' values when using ASYN/StreamDevice rather than telnet:
16.78
48.18
80.91
113.86
147.28
180.20
211.65
244.36
278.61
308.90
342.91
374.54
408.60
439.26
473.29
505.54



On Sep 26, 2010, at 2:40 PM, Mark Rivers wrote:

> Have you turned on asynTrace in the low-level (TCP?) driver and sent the output to a file so it does not slow things down too much?  Can you see then what's on the wire?
>
> Mark
>

--
Eric Norum
wenorum@lbl.gov