[Simh] EXT :Re: some performance issues

[gérard Calliet]

VAX hardware 89 VUPS

SIMH 27 VUPS

Gérard Calliet

Le 06/03/2019 à 19:46, Hittner, David T [US] (MS) a écrit :
> So from a performance analysis perspective, what are the VUPS ratings of the VS4000-90 and the SIMH VAX running on the RX2800?
> That's (more or less) the Integer performance rating.
>
> David
>
> -----Original Message-----
> From: Simh [mailto:simh-bounces at trailing-edge.com] On Behalf Of gérard Calliet
> Sent: Wednesday, March 6, 2019 1:11 PM
> To: Pontus Pihlgren <pontus at Update.UU.SE>
> Cc: simh at trailing-edge.com
> Subject: EXT :Re: [Simh] some performance issues
>
> Hi,
>
> We had a VAX Station 4000-90 128M Memory.
>
> We have a RX28000 9520 8G Memory.
>
> Gérard Calliet
>
> Le 06/03/2019 à 10:57, Pontus Pihlgren a écrit :
>> 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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