[Simh] performance issues vax / simh / openvms / itanium

[gérard Calliet]

No alignment faults seen.

Thanks,

Gérard Calliet


Le 24/04/2017 à 16:33, Wilm Boerhout a écrit :
> Does The compiler generate simh code that causes alignment faults when 
> simh executies? A notorious source of bad performance on early Itanium 
> ports.
>
> /Wilm
> Op ma 24 apr. 2017 om 14:22 schreef gérard Calliet 
> <gerard.calliet at pia-sofer.fr <mailto:gerard.calliet at pia-sofer.fr>>
>
>     Hello,
>
>     I have a VAX emulated with simh compiled and running on OpenVMS
>     8.4-1H1
>     (vsi) Itanium i4. The software used does only heavy cpu tasks (Ada
>     cross
>     compiler).
>     The performance is surprinsigly bad: about 4 times lower than then VAX
>     station 4000-90. A compilation batch which was taking 7mn of CPU takes
>     on the emulator 24mn of CPU.
>     The host Itanium uses 1 core at 100%, and not a lot of page
>     faults, 100
>     dio /s which I think is for the emulated clock.
>
>     (I use the same (back/image) system disk as of the initial
>     hardware VAX.
>     I have verified I use all the 512m of memory, there are not a lot of
>     page fault on the VAX.)
>
>
>     I don't understand why it is so bad. I thought about some special
>     things
>     on C compilation, but which?
>     Any suggestions?
>
>     Thanks,
>     Gérard Calliet
>
>
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