Wear, Mark (mark.wear++at++lmco.com)
Mon, 20 Sep 1999 15:39:46 -0600
It appears as though Irix 6.5.5 has corrected the problem. Testing on an
Onyx2 desk-side, I get no performance improvement by requesting a higher
frame rate.
Mark E. Wear
Senior Electronic Systems Engineer:
Real-Time Simulation
Lockheed Martin Missiles and Fire Control
(972) 603-2758
mark.wear++at++lmco.com
> ----------
> From: Baumgart, Donald[SMTP:donald.baumgart++at++cdott.com]
> Sent: Tuesday, September 14, 1999 10:35 AM
> To: Wear, Mark
> Cc: 'Info-Performer'; 'Info-Vega'; Baumgart, Donald; Boyle, Kris;
> Yamane, Dan; Silver, Nathan
> Subject: RE: Frame Rate
>
> Mark,
>
> Did the upgrade to IRIX 6.5.5 solve your problems??? Did it cause any
> problems with Vega?? We have a similar problem that may be related to
> this
> frame rate bug. We have used the 'npri' command to improve our situation.
> We are wondering if the upgrade is worth it right now, or will we run into
> more problems?
>
> Thanks for any info.
>
> Don Baumgart
> ----------------------------------------------------
> Don Baumgart
> System/Software Engineer
> Computing Devices Canada
> A General Dynamics Company
> 613-596-7454
> ----------------------------------------------------
>
>
> -----Original Message-----
> From: allan++at++southpark.engr.sgi.com [mailto:allan++at++southpark.engr.sgi.com]
> Sent: Wednesday, August 25, 1999 12:51 PM
> To: Wear, Mark; 'Info-Vega'
> Cc: 'Info-Performer'
> Subject: Re: Frame Rate
>
>
> On Aug 25, 7:25am, Wear, Mark wrote:
> > PROBLEM:
> > When I limit the frame rate to 30Hz, the simulation runs 30 Hz with
> frequent
> > drops to 20 Hz. However, when I limit the frame rate to 60 Hz, the
> > simulation runs 30 Hz with occasional jumps to 60 Hz (during roll). If
> the
> > simulation can run 30 Hz when asking for 60 Hz, why can it not run 30 Hz
> > when limiting to 30 Hz? What is going on here?
>
> I assume you're running IRIX 6.5.x. This is an IRIX bug that was
> introduced in IRIX 6.5 and just recently fixed for IRIX 6.5.5. The
> best overall solution would be to upgrade unless this causes problems
> for Vega. IRIX 6.5.5 is on the SGI website (support.sgi.com) and
> CD's should be shipping around now.
>
> Here's what's mentioned in the Performer relnotes;
>
> 6.1.1 Problems_fixed_in_IRIS_Performer_2.2.6
>
> o A change in the semantics of sginap() could cause
> frames to be missed if the application was running in
> FLOAT or LOCK phase and finishing its frame more than a
> full video field early. See Chapter 4 of these release
> notes for more details. This has been fixed in IRIX
> 6.5.5 (SCR 635983).
>
>
> [and from Chapter 4:]
>
> 4.1 IRIX 6.5
>
> In IRIX 6.5 through IRIX 6.5.4, a change in the semantics of
> sginap() can cause frames to be missed if the application is
> running in FLOAT or LOCK phase and finishing more than a
> full field early. The sginap() call is used by IRIS
> Performer specifically in the case where the application
> finishes more than a full field ahead of schedule. This
> does not affect applications running at field rate (ie. 60
> Hz) or applications running at their requested rate.
>
> A workaround is to give the program a realtime scheduling
> priority using the npri program (which must be run as root
> or with the CAP_SCHED_MGT capability):
>
> # npri -s RR -r <any number 0-255> <program> <args>
>
> or:
>
> # npri -s FIFO -r <any number 0-255> <program> <args>
>
> To allow users to run npri without full root permissions,
> you can give the npri program the set-capability-on-
> execution attribute:
>
> # chcap CAP_SCHED_MGT+eip /usr/sbin/npri
>
> If you later want to change it back:
>
> # chcap all= /usr/sbin/npri
>
> See the npri(1) and chcap(1) references pages for more
> information.
>
>
>
> --
> Allan Schaffer allan++at++sgi.com
> Silicon Graphics http://reality.sgi.com/allan
>
This archive was generated by hypermail 2.0b2 on Mon Sep 20 1999 - 14:40:34 PDT