[comp.unix.sysv386] AIX on Model 80 with X windows question

richp@romulus.la.locus.com (Richard L. Pettit Jr.) (09/05/90)

In article <14059@rouge.usl.edu> pcb@gator.cacs.usl.edu (Peter C. Bahrs) writes:
>I have a model 80 with 300mb hd, 8mb memory and a 20mhz processor.
>I have just loaded the new release of IBM AIX 1.2.  
>
>X Windows is kind of slow.  When I run ico -r, it doesn't move across the
>screen...it chunks across.  The mouse also freezes for small time
>periods and then catches up.
>
>I am using a 10mb page space.
>
>Any ideas on fine tuning this machine?

Buy a  math  co-processor.   Floating  point  in  AIX  1.[12]  is  done  by
attempting  to execute a 387 instruction and faulting into the kernel where
the 387 emulation is done in  software.   At  first  glance  this  type  of
implementation  looks pretty bogus, but in the long run, performance can be
regained by adding the co-processor and no recompilation needs to be  done.
The  387  instructions  will  be  executed  by  the  now   installed   387.
Flexibility at the cost of performance.  Don't shoot me, I'm only the piano
player.

Rich
----
              Richard Pettit                       Locus Computing Corp.
                                richp@locus.com
        "Opinions expressed herein are of the author, not (LCC or IBM)"

ken@dali.gatech.edu (Ken Seefried iii) (09/07/90)

In article <16887@oolong.la.locus.com> richp@romulus.UUCP (Richard L. Pettit Jr.) writes:
>In article <14059@rouge.usl.edu> pcb@gator.cacs.usl.edu (Peter C. Bahrs) writes:
>>I have a model 80 with 300mb hd, 8mb memory and a 20mhz processor.
>>I have just loaded the new release of IBM AIX 1.2.  
>>
>>X Windows is kind of slow.  When I run ico -r, it doesn't move across the
>>screen...it chunks across.  The mouse also freezes for small time
>>periods and then catches up.
>>
>>I am using a 10mb page space.
>>
>>Any ideas on fine tuning this machine?
>
>Buy a  math  co-processor.   

One more time kids...repeat after me...X is *not* floating point
intensive!  There is a *little* FP code in the arc drawing routines,
and some clients might use more or less FP, but in the general case a
387 doesn't buy you that much for X.

IMHO, the answer is:

1) More swap space.  On machines similar to yours at work (386/25s, 8MB
RAM, 330MB disks, SCO OpenDesktop) I use 16MB for general users, 24MB
for developers and especially heavy X users.  

2) More memory.  8MB is a minimum configuration for X.  I've found
(subjectively) in the past that 12MB is a pretty comfortable size for
me, doing Motif development and cranking up lots of clients.  16MB is,
of course a little nicer...:-) (for the cost of a 387/20, I think you
can buy almost 4MB of SIMMs, and that 4MB will go much farther).

N.B. - when you increase memory size, you also probably want to nudge
up swap size.  Swap == 2*(main memory size) seems to be the consensus
around here.

These are, of course, only my opinions...no warrenty expressed or
implied...

--

	ken seefried iii		ken@dali.gatech.edu

	"Vee haf veyz off making you talk...release da veasles..."

jag@aix.aix.kingston.ibm.com (Jay Goldberg) (09/10/90)

In article <14059@rouge.usl.edu> pcb@gator.cacs.usl.edu (Peter C. Bahrs) writes:
>I have a model 80 with 300mb hd, 8mb memory and a 20mhz processor.
>I have just loaded the new release of IBM AIX 1.2.  
>
>X Windows is kind of slow.  When I run ico -r, it doesn't move across the
>screen...it chunks across.  The mouse also freezes for small time
>periods and then catches up.
>
>I am using a 10mb page space.
>
>Any ideas on fine tuning this machine?

Sounds a lot like my configuration at work; here's what I did:

	/usr/sys/bin/ldminit -c patchdeck -l /unix

then reboot.  Here's the file 'patchdeck', which will let ldminit 
zap tunables in your kernel for you:

# PATCHDECK FILE
#
# patchdeck for ldminit that sets the configurable constants set in
# the master and system file.
# configuration for unix3
#
# change NPROC from 74 to 150 - Size of system process table
v+44:150:4
# change MAXUP from 25 to 100 - Max.number of procs per user
v+220:100:4
# change NFILE default = (240+(18*USERS)), 294 - Size of syste file table
v+12:500:4
# change default file size      default = 8192
def_f_lim:1000000:4

Also make sure you've configured plenty of pty's (>= 16).  This helped
me enormously; I hope it works out for you!

-----
Jay A. Goldberg 	| Email inside IBM:    KGNAIX(JAG)
Software Contractor	|		or     jag@aix.aix.kingston.ibm.com
Resource One Inc. 	| Email outside IBM:   uunet!ibmsupt!jag
Phone: (914) 336 7207	| Phone: (914) 385 3384 or 8+695 3384
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 > The opinions expressed above are those of the employee, not the Company <