[ECOS] Arm emulator

[ECOS] Arm emulator

[james chen]

Hi,
    I have setup a virtual hardware to let eCos run on it. it works fine,
but the performance is slow, I find that it was ARM instructions emulating
that takes many PC CPU resource. In my PC( CE333) I only get 1 MIPS in
emulating ARM instructions, are there any way to improve it. Thanks in
advance!

Best Regards,
james

Re: [ECOS] Arm emulator

[Cristiano Ligieri Pereira]

Which emulator is this? 
Can you give some pointer?

Such thing would be nice (at least for me) to do some experiments.

Thanks,
Cristiano.

------------------------------------------------------------
Cristiano Ligieri Pereira - http://www.ics.uci.edu/~cpereira

On Thu, 23 Aug 2001, james chen wrote:

> Hi,
>     I have setup a virtual hardware to let eCos run on it. it works fine,
> but the performance is slow, I find that it was ARM instructions emulating
> that takes many PC CPU resource. In my PC( CE333) I only get 1 MIPS in
> emulating ARM instructions, are there any way to improve it. Thanks in
> advance!
> 
> Best Regards,
> james
> 
> 
> 

Re: [ECOS] Arm emulator

[james chen]

I use arm-elf-gdb simulator, and have made some changes to it so it can
works with my virtual hardware( simulate to my custome test board )

>
> Which emulator is this?
> Can you give some pointer?

>
> Such thing would be nice (at least for me) to do some experiments.
>
> Thanks,
> Cristiano.
>
> ------------------------------------------------------------
> Cristiano Ligieri Pereira - http://www.ics.uci.edu/~cpereira
>
> On Thu, 23 Aug 2001, james chen wrote:
>
> > Hi,
> >     I have setup a virtual hardware to let eCos run on it. it works
fine,
> > but the performance is slow, I find that it was ARM instructions
emulating
> > that takes many PC CPU resource. In my PC( CE333) I only get 1 MIPS in
> > emulating ARM instructions, are there any way to improve it. Thanks in
> > advance!
> >
> > Best Regards,
> > james
> >
> >
> >
>
>
>

Re: [ECOS] Arm emulator

[Jonathan Larmour]

james chen wrote:
> 
> I use arm-elf-gdb simulator, and have made some changes to it so it can
> works with my virtual hardware( simulate to my custome test board )

That's probably the ARMulator. You could instead try SID:
http://sources.redhat.com/sid although I'm afraid I don't know how it
compares performance-wise.

Jifl
-- 
Red Hat, Rustat House, Clifton Road, Cambridge, UK. Tel: +44 (1223) 271062
Maybe this world is another planet's Hell -Aldous Huxley || Opinions==mine

Re: [ECOS] Arm emulator

[james chen]

Hi, Jifl:

     thanks, I'll try SID when I have time. in fact, emulate ARM
instructions on PC will only get 2-5 MIPS, what can we do in that too low
performance CPU, especially run multi-task.

          but now I have changed into linux synthetic, modify linux_entry.c
and linux_intr.c in HAL, use linux memory image file to communicate between
eCos and  peripheral equipment simulator application, and write a new I/O
driver, it works fine.

        BTW, I have sent a mail which subject is *catch errors in eCos's
kernel* near Sep, 1. have you confirm it and checked it in CVS?

Best Regards,
james


> james chen wrote:
> >
> > I use arm-elf-gdb simulator, and have made some changes to it so it can
> > works with my virtual hardware( simulate to my custome test board )
>
> That's probably the ARMulator. You could instead try SID:
> http://sources.redhat.com/sid although I'm afraid I don't know how it
> compares performance-wise.
>
> Jifl
> --
> Red Hat, Rustat House, Clifton Road, Cambridge, UK. Tel: +44 (1223) 271062
> Maybe this world is another planet's Hell -Aldous Huxley || Opinions==mine
>
>

Re: [ECOS] Arm emulator

[Frank Ch. Eigler]

"james chen" <james_ch1@sina.com> writes on ecos-discuss:

: [...] I find that it was ARM instructions emulating that takes many
: PC CPU resource. In my PC( CE333) I only get 1 MIPS in emulating ARM
: instructions [using an enhanced gdb/arm simulator], are there any
: way to improve it. [...]

A target:host instruction ratio of 1:100 is about typical for an
instruction set simulator that uses ordinary fetch/decode/execute
algorithms.  Advanced interpretation techniques like cached decode
structures, native host translation, can help a lot, but are pretty
hard to create.

The sid simulator uses an ARM kernel generated by the cgen tool (both
on http://sources.redhat.com/ ), and it does have a small degree of
this sort of thing, but I don't know how it performs in comparison to
the old armulator snapshot (gdb's arm sim).  sid has a feature that
may assist simulation speed in an indirect way: state save/restore,
which lets you theoretically rerun a program from a saved snapshot.
That saves time in skipping e.g. initialization.

Apart from these, and simple mechanical improvements (like compiling
everything with maximum optimization), I can't think of a way of
significantly improving speed.

- FChE