[Info-vax] What would be involved in moving RMS into kernel mode ?

[Simon Clubley]

On 2023-05-04, Johnny Billquist <bqt at softjar.se> wrote:
> On 2023-05-02 15:24, Simon Clubley wrote:
>> If the emulated executive mode is a major reason for the kernel overheads
>> we are seeing on x86-64 VMS, what would be involved in moving RMS from
>> executive mode directly into kernel mode ?
>
> I have a hard time seeing why it would cost very much to deal with the 
> different modes.

In which case Johnny, you have no clue about the overheads involved here
when emulating a processor mode in software.

I also suspect you have no clue either about why I keep asking about kernel
overhead on AMD systems and what the significance of that question is.

> I can definitely believe that code hasn't been 
> optimized in general, though.
>

At best, that's only a small contribution to the numbers that Mark
is seeing. Also, don't forget that the E/S emulation code is new code,
not ported existing code.

A percentage is a ratio and unless there's any evidence that better
compilers would affect the code running on one side of that ratio much
more than the other side, then the overall percentage should still remain
roughly the same even with better compilers.

I also note that VSI have not responded to Mark's question after the
better part of a week. That's not a good look.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.