[omniORB] Latencies - Oneway vs. Roundtrip

bjornw@fairplay.no bjornw@fairplay.no
12 Apr 1999 20:48:55 +0200

"Gary D. Duzan" <gdd0@gte.com> writes:

> In Message <3711F5E0.6BBEDC4E@datarespons.no> ,
>    "Helge Penne" <Helge.Penne@datarespons.no> wrote:
> =3D>My theory is that omniORB buffers my oneway calls and sends them in=
> =3D>packages every 200ms (5Hz).  This explains every symptom that I hav=
e seen, and
> =3D>also fits in nicely with my previous experience with VisiBroker.  V=
> =3D>also buffers such requests by default, but there is an option in BO=
A_init that
> =3D>lets you turn off this buffering and force these requests to be sen=
> =3D>immediately.
> =3D>
> =3D>This leads up to a very important question: How do we turn off this=
> =3D>in omniORB?  This is quite an important question for my project.  H=
as anybody
> =3D>done this before?
>    My guess would be that it is your TCP stack doing the buffering. On
> AIX, at least, there is a TCP_NODELAY option (for use with setsockopt()=
> which turns off the "Nagle algorithm for deciding when to send data".
> You might look to see if the NT socket API has something similar. If
> so, OmniORB could be modified to use it. (I should probably put togethe=
> a patch for AIX to use TCP_NODELAY, actually.)
> 					Gary Duzan
> 					GTE Laboratories
In my previous project I experienced exactly the same when we changed som=
e equipment; the=20
packages suddenly appeared every 200ms. We did use a modem-pool with scsi=
 interface but=20
wanted to exchange that equipment with an ethernet-based modem-pool. This=
 box had=20
hard-coded a delay of 200ms per packet unless each tcp package were fille=
d. On some
equipment the manufactorer have been clever and provided options to set t=
hrough the drivers,
but not all :-( (we had to switch back to the old scsi interface....)

You may want to check every component along the line between the sender a=
nd the receiver
to assure that it's not a hardware feature you are experiencing.

Bj=F8rn Wennberg              email: bjornw@fairplay.no=20
                               ms: +47 950 82 657
Senior Programmer           phone: +47 22405538
FairPlay International AS     fax: +47 22405539