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From: tim@proton.amd.com (Tim Olson)
Newsgroups: comp.unix.questions
Subject: Re: System turns into pig after 66040 installation on HP-UX
Message-ID: <1991May9.183859.27426@dvorak.amd.com>
Date: 9 May 91 18:38:59 GMT
References: <26810@adm.brl.mil>
Sender: usenet@dvorak.amd.com (Usenet News)
Reply-To: tim@amd.com (Tim Olson)
Organization: Advanced Micro Devices, Austin, TX
Lines: 30

In article <26810@adm.brl.mil> FLYNN%EVALUN11.BITNET@cunyvm.cuny.edu (Mark F. Flynn) writes:
| We're running HP-UX 7.05 on an Apollo 400t, and have just installed the
| new and wonderful 68040 processor. What we have noticed is that certain
| jobs spend from 50% to 90% of their time doing system calls, as opposed
| to user time. This is reported both by "time" and a command we have
| here called "monitor". I havn't figured out what sort of code actuall
| produces this yet. So far, we have only seen it on Fortran code, but
| this may just be that we havn't run the right (or wrong) C program yet.
| Optimization levels have no signifigant effect. Changing the type
| of cacheing similar does nothing.
| 
| The HP people here havn't a clue. Has anyone experienced a similar problem?
| Any suggestions? Thanks in advance.

Is the code that is running an old binary that used to run on a
previous 680{20,30}/68882 system?  If so, there may be floating-point
coprocessor instructions for trancendentals (sin, cos, etc.) in the
code.  The 68040 does not implement these instructions, but rather
causes a trap.  The system may be performing emulation of these
instructions in the kernel.

If this is the case, you might try recompiling the programs -- they
would probably use user-mode library routines for trancendentals on
the 68040 which would be much faster.


--
	-- Tim Olson
	Advanced Micro Devices
	(tim@amd.com)