The reason was "you can do everything with 2 OpenVMS/Itanium boxes"
(they are Itanium I4)
Gérard Calliet
Le 06/03/2019 à 16:54, Zane Healy a écrit :
I have to wonder if a lightweight Linux disto, that has been locked down,
running on a Core i7 might not give better SIMH performance. My *old* i7 ESXI
box provides a faster “VAX” than my VAXstation 4000/60.
What is the reason for running on Itanium?
Zane
On Mar 6, 2019, at 1:57 AM, Pontus Pihlgren <[email protected]> wrote:
Hi
I'm having trouble understanding your question. Are
you comparing CPU-time of a real VAX(which model?) to
emulated CPU-time on an Itanium machine(which one?).
Emulation will have an associated overhead. If you
are compareing a fast VAX to an emulation on a slow
Itanium... well, Itanium is hard to optimize for.
/P
On Tue, Mar 05, 2019 at 03:13:53PM +0100, gérard Calliet wrote:
Hello,
Again I have some performance issues with simh.
I built it on OpenVMS Itanium. It runs on a process with enought
memory, it takes 1 of the 8 CPU Itanium with 100%, no page faults,
and 100 BIO by second.
On the emulated VAX we are running processes CPU intensive (old Ada
compiler), they take 100% of the CPU, also very few page fault, very
few IO.
And the CPU time is about 2 or 3 times the CPU time on the hardware,
and so elapsed time 3 or 4 times. (For my understanding, it is
difficult to think the same stream of instructions can use different
CPU times between hardware and SIMH).
Where can I do something to improve performance? Are there
parameters (or constant in compilation) in SIMH which could help?
And the specific context is processes doing almost only CPU
computing.
my configuration, and what commit I use
on error continue
load -r ka655x.bin
attach NVR ka655.nvr
set cpu 512m
set cpu conhalt
set RL disable
set LPT disable
set TQ disable
set -L rq0 rauser=18000000
attach rq0 datauser2.dsk
set xq mac=08-00-2B-3C-96-75
attach xq eth0
dep bdr 0
b cpu
$ run vax-i64
MicroVAX 3900 simulator V4.0-0 Beta git commit id: 8810571d
sim>
Thanks,
Gérard Calliet
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