Re: TN5250E Printing Speed -- LINUX5250

Dear James,

I confirmed with Jeffery Stevens of IBM when V5R1 was released that the
Telnet server currently shipped within OS/400 has an approximate maximum
throughput capability of about sixty-five (132 column by 66 row) pages per
minute for each TN5250E printer pass through session configured on an
iSeries host. He told me that IBM knows how to improve the supported
throughput (so that the pages per minute value would be greater) but that
the resources to implement these improvements would most likely only be
assigned if IBM received requests for faster TN5250E printing speeds from
actual customers.

You might have hit this host side TN5250E printing speed bump with your
test.

Best Regards,

/Paul
--
Paul Tykodi
National Product Manager
LCI-Intermate US, Inc.

p: 603.431.0606 x115
f: 603.436.6432
paul@intermate-us.com
www.intermate.com

>Date: Mon, 11 Mar 2002 18:13:59 -0700 (MST)
>From: James Rich <james@eaerich.com>
>To: linux5250@midrange.com
>Subject: Re: [LINUX5250] scs2pdf thoughts
>Reply-To: linux5250@midrange.com
>
><large snip>
>
>Good to hear.  But that only makes sense:  enscript/ps2pdf is two
>conversions, scs2pdf is really none.  And scs2pdf is simple code.  It
>should run really fast.  I did some investigating since we use scs2pdf on
>some big print files and found that the system (unix box) spends most of
>its time in lp5250d, and almost none in scs2pdf.  I'm guessing that is
>because lp5250d is copying data from the network socket to stdout.  Here
>is what I did (not fancy at all):
>
>1.  Sent a 7,880 page spoolfile to my (lp5250d/scs2pdf - connected) PDF
>printer.
>2.  top reports that lp5250d uses about 40% of CPU, scs2pdf uses about 4%
>3.  Total time is about 23 minutes, load average was about 0.53 on a not
>very fast P233 running gnome and mozilla.
>4.  Resent the same report to scs2pdf by feeding the raw printer output
>directly to scs2pdf (i.e. lp5250d outputcommand=cat > /tmp/rawfile then
>put that through scs2pdf: scs2pdf < /tmp/rawfile > /tmp/outfile.pdf).
>That took less than two minutes.
>
>Now of course the first was sent over the network and the second was all
>on local disk so they aren't real comparisons.  The raw print file is
>41311794 bytes and the resulting PDF file is 49742066 bytes.  What is
>interesting is that lp5250d/scs2pdf didn't eat more CPU, especially
>considering that the CPU was partly idle.  This probably means that the
>unix machine could have received and processed more data faster if it had
>been available.  Processing the output from scs2ps with ps2pdf takes far
>longer.
>
>I'm not sure if I'm saturating our network capabilities with this test or
>if our iSeries just can't put data on the wire any faster.  At any rate,
>the box I'm working on is not the limiting factor here, and this box is
>puny.  I think that I could do three simultaneous print jobs like that and
>not experience any slowing due to my box.  But I can't test that since I
>only have one iSeries and it is on a 16 Mbps token ring segment.  But if I
>had three all on the 100 Mbps switch that I'm on I bet it would scream.
>
>James Rich
>james@eaerich.com